University of California

For Abstracts

A Quafety approach to quality monitoring and prediction for fresh-cut produce

Giancarlo Colelli(Department of Science of Agriculture, Food and Environment, University of Foggia , Italy )

Quafety is a neologism which entails to a global approach in considering quality and safety of a food product as a composite strategy leading to a sole, all-inclusive objective, consisting of full satisfaction of consumer in terms of sensorial and nutritional expectations, with no harmful effect associated with the consumption. QUAFETY is the short name for a collaborative 3-year R&D project co-funded by the European Commission (Comprehensive Approach to Enhance Quality & Safety of Ready-to-eat Fresh Products), aimed to improve safety and quality of ready-to-eat fresh produce throughout the whole chain, and participated by 14 partners among public research Institutions and small and medium enterprises, from 7 Countries (including Italy, UK, Portugal, Poland, Netherlands, Greece, and Israel), assorted in terms of scientific and technological expertise. Objectives of the project were reached by developing diagnostic kits to predict quality and safety of raw material and final product, process control aids based on non-destructive and rapid evaluation methods, decision support tools in very critical points of processing chain, and by investigating innovative processes. Monitoring and prediction is part of the “quafety approach” both in terms of early detection and of estimation of fate for main quality attributes. Among others, results will be described on using antibody arrays for the identification of molecular markers to predict quality and microbial contaminants, on non-destructively monitoring quality through SPME volatile organic compounds collection and analysis, and on predicting nutritional quality based on external attributes degradation kinetics. Project QUAFETY has officially ended on March 31, 2015.

Affect of firming and anti browning agents on the quality characteristics of fresh-cut Guava fruit at different temperature

Muhammad Inam-ur- Raheem, Aman-Ullah Malik,Nuzhat Huma,Hafiz Khuram wasim Aslam,Azam Shakeel and Hafiz Arbab sakandar

Present study was conducted in three phases to evaluate the effectiveness of firming and anti-browning agents alone (Phase-I and II) and in selective combinations (Phase-III) stored at low temperatures on the quality of fresh-cut guava slices. In all phases, uniform sized guava were picked, washed, sliced, treated and subjected for different analysis at 0, 6, 12, 18, 24 days of storage. In first phase guava slices were treated with different concentrations of firming (calcium chloride and calcium lactate) and anti-browning (ascorbic acid and cysteine) agents at 5 degrees C and analyzed for different physiochemical characteristics (firmness, browning, colour and organoleptic characteristics) to select most appropriate concentration from each chemical agent. While in the third phase, guava slices of two guava varieties (Surahi and Gola) were treated with the different combinations of best concentrations of firming and anti-browning agent and kept at two different temperatures (5 degrees C and 10 degrees C) and analyzed for various physiochemical characteristics (firmness, browning, colour, weight loss, pH, acidity, TSS, calcium, cysteine, lipase activity, organic acid, microbial count and organoleptic characteristics) to find out the most effective combination in extending the self-life of fresh-cut guava slices. As a result, in first phase, 2.7% calcium chloride and 3.6% calcium lactate maintained firmness, delayed browning and maintained the other characteristics of guava slices for longer storage interval. Whereas, in the second phase, 1.8% ascorbic acid and 0.8% cysteine were helped to delay browning and maintained better organoleptic characteristics throughout the storage period. However, in the third phase, the combination of 2.7% calcium chloride and 1.8% ascorbic acid gave overall best results than other treatments in most physico-chemical and organoleptic characteristics, especially of Gola variety, at 5 degrees C till 12 days.

Breeding lettuce for fresh-cut processing

Ryan J. Hayes (United States Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, 1636 E. Alisal St, Salinas, CA 93905)

Ivan Simko (United States Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Unit, 1636 E. Alisal St, Salinas, CA 93905)

Lettuce is increasingly consumed in fresh-cut packaged salads. New cultivars specifically bred for this use can enhance production and processing efficiency and extend shelf life. Cultivars with novel head architectures and leaf traits are being released by private and public breeding programs with the goal of increasing consumer appeal, increasing yield, or decreasing waste. Cultivars grown for processing require elevated resistance to tipburn (TB) and improved shelf life. Multiple field experiments with three lettuce populations determined that tipburn incidence has low heritability, large genotype x environmental interactions, and significant genetic correlations with head morphology. Several morphological traits that promote low TB are undesirable for fresh-cut processing. Improved TB resistance is needed most in romaine cultivars. Romaine lines with enhanced TB resistance have been selected from iceberg x romaine crosses, though further improvements are needed. Accessions with genes conferring resistance to viral, fungal, and bacterial diseases have exceptionally rapid decay as fresh-cut salad, which has prevented adoption of these resistances by the lettuce industry. The genetics of rapid decay was investigated in two recombinant inbred line populations of lettuce grown in six field experiments. A large effect quantitative trait locus (QTL) was mapped to chromosome 4 and had limited QTL x environment interactions. Breeding lines combining disease resistance and slow decay have been released and molecular markers for use in marker-assisted selection for slow decay are under development. The biology of shelf life is poorly understood. Cloning the gene controlling this QTL may improve our understanding of fresh-cut lettuce decay.

Comparative evaluation of hydroponic and soil grown “Española” lettuce.

María L. Tapia, Werther Kern, Víctor H. Escalona y L. Antonio Lizana (Centro de Estudios Postcosecha (CEPOC), Facultad de Ciencias Agronomicas, Universidad de Chile, Santa Rosa 11315, La Pintana. P.O. Box 1004, Santiago, Chile. website:

Hydroponic grown lettuce usually sold at 20 to 30 % higher prices at local consumers markets, compared with same soil grown type, both at equal presentation, which includes individually wrapped in plastic bag . Some concern have resulted by indications that hydroponic growing systems may induce higher nitrates content in lettuce and also that cost involved in its production would be adverse in their profit.

Espanola type of lettuce were purchased at local markets, or obtained directly from production field, and analyzed at the CEPOC post-harvest laboratory during the month of Jan and Feb. Nitrate levels in hydroponic grown lettuce (flood root system and “Nutrient film Technique” (NFT) fluctuated between 1344 and 3.839 mg/kg. none reached European Commission´s maximum tolerance levels of 4.500mg/kg (FW). Average cost registered per unit, was US$ 0,08 dl, compared with US$ 0,13 dl of conventional soil grown lettuce in Chile. Also we calculate the hydroponic cultivated lettuce water footprint being the in the level of 19 m3 ton-1, value very low compared to the soil extensive cultivation of 237 m3 ton-1. The reverse analysis of the obtained values, indicated an average level of productivity of 53 g of lettuce (one unit)/ liter of water used for the hydroponic grown lettuce compared to 13 liters to produce each unit in the soil grown system. (4 g/liter). If consider the return price to grower was $170 pesos/unit (0,28 US dl/unit) the unit profit per liter of used water (estimated value US $ $ 0,0017/L) the value in the hydroponic unit crop was US$ 170 per dollar, and the soil grown lettuce, US$ 13 per dollar invested in water.

Hydroponically grown Espanola type lettuce, uses less water/unit to grow (water footprint) had better appearance, less damage in peripheral external leaves, cleaner presentation and a better market quality than traditional soil grown ones.

Comparison of the Organic and Conventional Agricultural Practice on the Quality and Antioxidant Activity of Welsh Onion

Min-Sun Chang1, Shin-Young Lee1, Moon-Cheol Jeong2, Gun-Hee Kim11DukSung Women’s University, 2Korea Food Research Institute

Consumers are aware of their health and more conscious of environmental conditions. There is an increasing demand for agri-foods obtained from organic agricultural practices. The present study aimed to compare the quality characteristics and antioxidant activities between organically and conventionally grown welsh onion (Allium fistulosum L.). The weight, length, diameter, moisture contents and color (Hunter L, a, b) were measured for the quality characteristics. In addition, total phenols, total flavonoids, and the DPPH and ABTS radical scavenging activities were analyzed for the antioxidant activities of organically and conventionally grown welsh onion. The weight, length, diameter, and moisture contents were similar between the organically and conventionally grown welsh onions. The L (lightness) values of the organic welsh onion were higher than the conventionally grown ones (p<0.05). The total phenol contents were 90.77 mg GAE/g in the organic and 81.10 mg GAE/g in the conventional welsh onion. The total flavonoid contents in organically cultivated welsh onion were significantly higher than the conventional welsh onions (p<0.001). The respective DPPH and ABTS radical scavenging activities were 4.71% and 18.21% in the organically grown welsh onion and 4.72% and 18.05% in the conventionally grown welsh onion. Therefore, organically grown welsh onion were found to have better compositional quality than product.

Effect of chemical compounds and hot water on quality of fresh cut white cabbage

Tapia C. and Valencia-Chamorro S. (Departamento de Ciencia de Alimentos y Biotecnología, Escuela Politécnica Nacional, Quito Ecuador

The effects of the addition of chemical compounds classified as generally recognized as safe (GRAS), and hot water, on fresh cut cabbage were studied. Strips were prepared from cabbages and treated with solutions of acetic acid (0.15 w/w), ascorbic acid (0.2% w/w)-citric acid (0.5% w/w) combination, potassium sorbate (0.2% w/w), and water as control. Treated samples were packed in polypropylene (PP) bags and stored at 4 degrees C for 12 days. Physical, chemical, microbiological and sensory analyses on treated samples were performed. Samples treated with ascorbic-citric acids combination exhibited lower browning index (BI), lower microbial contamination and better sensory attributes than the other samples. On a next experiment, this chemical treatment was selected to compare with samples immersed in hot water. Then, strips cabbages samples treated with ascorbic-citric acids combination, dip in hot water (60 degrees C), and water as control, were packaged in (PP) and low density polyethylene (LDPE) bags, and stored at 4 degrees C for 12 days. Samples with hot water treatment showed a weight loss less than 0.2%, and lower carbon dioxide accumulation inside the bags, than other samples. In this treatment, total polyphenols content was reduced by around 15.5% regarding to the initial sample (363 mg/100g as % gae). However, BI was the highest. Ascorbic-citric acids combination treatment showed a weight loss less than 0.5%. This treatment maintained microbiological and sensory quality of samples during the storage time. Total polyphenols content was increased by 8.2%. Ascorbic-citric acids combination treatment may be an alternative for fresh cut white cabbage

Effect of Nitrogen Concentration in the Nutritional Solution and Harvest Time on Nitrate Content in Baby Leaves of two Swiss-Chard Cultivars Crop in a Hydroponic System

Vanegas David(1), Contreras Antonia(1), Tapia María Luisa(1), Lizana Luis Antonio(1,2), Escalona Víctor(1,2).1:Centro de Estudios Postcosecha. Facultad de Ciencias Agronómicas. Universidad de Chile.2:Departamento de Producción Agrícola. Facultad de Ciencias Agronómicas. Universidad de Chile. Santa Rosa 11315, La Pintana, P.O. Box 1004, Santiago, Chile. website:

The development of baby leaf vegetables has increased due to its fast processing operations and its attractiveness as a gourmet product. Despite these benefits, its high level of nitrates in tissues will create serious health problems. To reduce these levels, the dose of nitrogen fertilization and harvest time are essential. The objective of this study was to evaluate the nitrate content in two cultivars of Swiss-chard (baby leaf) changing the N2 content of nutrient solution and time of harvest. For this, two independent assay were performed, where the nitrate content, nitrate reductase activity (NRA) and quality parameters such color, dry weight, height of leaf were measured in two cultivars of Swiss-chard (Beta vulgaris L. var. Cicla) with a red (E1) and orange petiole (E2), respectively. A randomized split-plot design was performed, where the main plot corresponded to N2 dose (100, 200, 300 and 400 mg N2 L¯¹) and subplots of different harvest times (9, 12 and 21 h). In E1, the time of harvest was the main factor on the nitrate content, where high N2 levels were founded at 8 h, and low levels at 12 and 21, probably due to different carbohydrate levels and reducing supplying powers available to activate the NRA, which had its maximal activity at 12 and 21 h. By contrast, in E2 the N2 concentration in the nutrient solution had a significant effect on the content of nitrates, where high dose caused a high accumulation in tissues. In both assay, increased nitrate content in the petiole and midrib compared to the lamina was obtained.

Effect of wounding intensity and methyl jasmonate pretreatment on phenolic compounds and antioxidant capacity of fresh-cut pitaya fruit

Xiao-an Li (Nanjing Agricultural University)Fan Gao (Nanjing Agricultural University)Qing-hong Long (Nanjing Agricultural University)Chen Chen (Nanjing Agricultural University)Peng Jin (Nanjing Agricultural University)Yong-hua Zheng (Nanjing Agricultural University)

The effect of different degrees of wounding stress and a pre-cutting methyl jasmonate (MeJA) treatment on phenolic compounds and antioxidant capacity of fresh-cut pitaya fruits during 4 days of storage at 15 degrees C was investigated. For the wounding intensity study, pitaya fruit were cut into slice (1cm thickness), half-slice(1/2 section from a slice of 1cm thickness) and quarter-slice(1/4 section from a slice of 1cm thickness) to generate different wounding intensities, with the intact pitaya fruits without any wounding as the control. For MeJA pretreatment study, intact pitaya fruits were first treated with 0, 1, 10 or 100µmol/L of MeJA and then cut into quarter-slice. Total soluble phenolics (TSP), antioxidant capacity (AOX) and phenylalanine ammonia-lyase (PAL) activity in all fresh-cut produce increased significantly during storage compared with whole pitaya fruits. This enhancement in TSP, AOX and PAL activity increased with wounding intensity. Increases in reactive oxygen species (ROS) production was also observed in all fresh-cut pitaya fruit. Pre-cutting treatment with 100µmol/L of MeJA further promoted the increase in TSP, AOX, PAL activity and ROS production in quarter-sliced pitaya fruit. These results demonstrated that increasing wounding intensity and pre-cutting MeJA treatment can improve the biosynthesis of phenolics compounds and enhance the antioxidant capacity of fresh-cut pitayas. ROS may play a key role as signaling molecules in wounding-induced biosynthesis of phenolic compounds in fresh-cut pitaya fruits.

Effective combination treatments in maintaining the quality and extend the storage life of freshly peeled onion

Zaulia O., Azhar M. N., Muhd Amin R., Razali M., Nur Aida M. P., Bizura Hasida M. R., Latifah, M.N., Wan Mohd Reza Ikwan W.H., Nur Azlin R., Nur Syafini G., Siti Aisyah A., Joanna C.L.Y., Habsah M., Syed Abas S.A.R., Hairiyah M., Zaipun M. Z., Tham S.L., Mohamad Fikkri A.H. , Ismail M., Zainab M.Y. and Siti Khuzaimah T. Horticulture Research Centre, MARDI Headquarters, Persiaran MARDI-UPM, 43400 Serdang, Selangor, Malaysia

High quality and long storage life of peeled onion can reduce post-harvest losses significantly and improve food safety. Freshly peeled onion is convenient, ready to eat, ready to process or ready to cook and very useful for food services and processing industries to help facilitate and expedite the processing and preparation of food as well as optimizing the use of labour. However peeled onion without proper technology has a short storage life (1-2 weeks) due to rooting, sprouting and fungus growth, discolouration and development of strong off-odour.Combination treatments to produce high quality peeled onion resulted from various studies to prolong storage life from 1-2 weeks to 8 weeks at 2 degrees C. Combination treatments involved various factors including the use of high quality raw materials, skin peeling, washing, trimming (double trimming), drying (spinning), treatment (UVC and ethylene absorber), use of the most suitable packaging (retail - polypropylene, bulk-0.04mm LDPE ) and active packaging materials (ethylene absorber), the optimum storage temperature (2 degrees C), chilled and hygienic processing and storage area, skilled and trained workers and ensuring cold chain along the chain. Active packaging materials such as oxygen absorbers, ethylene absorbers, nanosilver packaging (1%) and UVC treatment (240nm, 5-10 min) were effective to slow down browning, root and shoot growth and fungal growth, and maintain colour and ascorbic acid content.

Effects of heat treatment prior to cutting on quality attributes and storability of fresh-cut Chinese yam

Hetong Lin (College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China); Yihui Chen (College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China); Yen-Con Hung (Department of Food Science and Technology, University of Georgia, 1109 Experiment Street, Griffin, GA 30223, USA); Yifen Lin (College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China); Meirong Fan (College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China)

In order to evaluate the possibility of heat treatment prior to cutting for maintaining quality and increasing storability of fresh-cut Chinese yam (Dioscorea opposita Thunb.), fresh tubers cv. Shangehuaishan No.1 were washed with tap water to remove soil and other foreign matter, dipped in 200 mg/L chlorine hypochlorite for 10 minutes to surface-sterilize, treated with hot-water at 35, 40, 45 degrees C for 30 min, then peeled and cut into approximately 30-mm blocks. The cut yams were rinsed with distilled water, then air-dried and packed into sealed polyethylene bags (0.015 mm thickness) and stored at 4 degrees C for 10 days. At 2-day intervals, the CIE (Commission Internationale de L'Eclairage) parameter of L*, the browning index, the value of browning degree, polyphenol oxidase (PPO) activity, weight loss, total sugars and respiration rate were determined. The results showed that compared to the untreated hot-water yam samples, hot-water (35, 40, 45 degrees C) treatment exhibited significantly higher L* values, lower browning index, lower PPO activity, lower weight loss and lower respiration rate, and higher contents of total sugars. Among the hot-water-treated yam samples, hot-water at 45 degrees C for 30 min was the most effective treatment in maintaining quality and increasing storability. These results indicate that the hot-water treatment at 45 degrees C for 30 min prior to cutting might be a feasible technique for maintaining quality and increasing storability of fresh-cut Chinese yam during storage at 4 degrees C.

Estimation of degradation of internal attributes of fresh-cut produce based on external quality

Amodio M.L., Derossi A., Mastrandrea L., Dechiara M.L.V., Colelli G. (Department of Science of Agricultural, Food and Environment, University of Foggia, Italy)

The aim of this work was to find a relation between degradation patterns of internal and external attributes of fresh-cut fruits and vegetables to be used as a fast method to estimate the rate of degradation of internal quality based on easy quality indicators. Model crops included melon and pineapples as fruits, and rocket leaves, iceberg and lamb lettuce as vegetables. All samples were stored in passive modified atmosphere at 0, 5 and 15 degrees C for a maximum of 11 days. External and sensorial attributes such as visual appearance, off-odor, aroma, and color were monitored, whereas as internal quality attributes ascorbic acid, phenolic content and antioxidant activity were assessed. Both first-order kinetic and Weibullian model were compared for the ability to fit the kinetic of quality degradation over time. Weibullian model gave more accurate results than conventional kinetics, accounting for 85 to 99% of the variance of experimental data. After the individuation of internal and external quality markers for each product, and considering that the time was the common variable among the mathematical models, a new mathematical equation was obtained. In all case a good correlation between internal and external quality attributes was found. Generally, a reduction of 20% of ascorbic acid was observed for all studied products at 5 degrees C when they reached the limit of marketability (score of 3). Also, the same reduction of ascorbic acid was shown to be related with 40% of reduction of O2 concentration. Useful correlation were also found between off-odor and ascorbic acid for lamb lettuce (r2 = 0.90) and for firmness and appearance score for iceberg lettuce (r2 = 0.90).

Ethanol fumigation can effectively inhibit the browning of fresh-cut burdock

Tiantian Dong, College of Food Science and Engineering, Shandong Agricultural University, Tai’an, 271018, China.Yanyan Feng, College of Food Science and Engineering, Shandong Agricultural University, Tai’an, 271018, China.Jingying Shi, College of Food Science and Engineering, Shandong Agricultural University, Tai’an, 271018, China.Marita Cantwell, Mann Laboratory, Department Plant Sciences, University of California, Davis, CA 95616, USA.Qingguo Wang, College of Food Science and Engineering, Shandong Agricultural University, Tai’an, 271018, China.Yalin Guo College of Food Science and Engineering, Shandong Agricultural University, Tai’an, 271018, China.

Burdock (Arctium lappa L.) known for centuries in China and other Asian countries has been eaten as root vegetable or medicinal plant. It has high nutritional value, healthy effects, high antibacterial activity, antioxidant activity and free radical scavenging activity. Fresh-cut burdock is susceptible to browning. The purpose of this research was to investigate the effect of ethanol fumigation on inhibiting browning of fresh-cut burdock. In our experiments, burdocks were fumigated with ethanol for 12 hours before cutting or for 5 hours after cutting, then stored at 2~4 degrees C. The results showed that pre or post cutting can effectively inhibit the browning of fresh-cut burdocks. The control slice was browning on day 2, but the treated slices still had good color on day 6-10 in different experiments. Ethanol fumigation reduced the respiration rate, lowered the activity of PPO and PAL, and the content of total phenolic content of fresh-cut burdock. Besides, ethanol fumigation also increased the content of H2O2, enhanced the antioxidative capability through DPPH inhibition and CAT activity and decreased the content of MDA. The results indicate that ethanol fumigation can extend the shelf life of fresh-cut burdock by inhibiting its browning and maintaining its quality.

Extending postharvest life of ready-to-use zucchini flowers: effects of the atmosphere composition

Maria Cefola (Institute of Sciences of Food Production, CNR - National Research Council of Italy Via G. Amendola, 122/O – 70126 Bari, Italy) Maria Luisa Amodio and Giancarlo Colelli (Dept. SAFE, University of Foggia, Via Napoli 25, 71122 Foggia, Italy)

Zucchini male flowers (Cucurbita pepo L.) are greatly appreciated by consumers although, due to their high perishability, they are destined only to local markets. The effects of four different atmosphere compositions (air, 3% O2 in nitrogen, 3% O2 + 10% CO2 in air, and 10% CO2 in air) on quality attributes of cut zucchini male flower(color, weight loss, respiration, fermentative volatiles, and vitamin C) were studied. Storage in controlled atmosphere significantly (P<0.05) affected postharvest quality and marketability of ready-to-use zucchini flowers. At 5 degrees C atmosphere containing 3% O2 in nitrogen determined a reduction in respiration rate and weight loss, and allowed to preserve visual appearance, sensorial and nutritional quality, maintaining the Vitamin C content during the entire cold storage. In this condition fresh zucchini flower were scored still marketable and with a good appearance after 9 days of storage. On the other hand flowers stored in air deteriorated rapidly, resulting just above the limit of marketability (score 3) after 5 days of storage whereas the adding of CO2 to air only slightly increased the flowers shelf-life. Flowers stored in air (with or without CO2) showed the same spoilage symptoms, defined by water soaking, wilting and brightness loss which were reduced in low oxygen atmosphere. Based on these results the proper atmosphere conditions for zucchini male flowers should attain low oxygen levels (3%) which allowed to preserve nutritional quality and fresh appearance of zucchini flowers, avoiding excessive accumulation of CO2.

Fresh-cut Kale Quality and Shelf-life in Relation to Leaf Maturity and Storage Temperature

Karin Albornoz (Dept. Plant Sciences, UC Davis, Davis CA 95616) and Marita Cantwell (Dept. Plant Sciences, UC Davis, Davis CA 95616)

Kale (Brassica oleracea var. Acephala) is a very nutritious leafy vegetable and its consumption in fresh cut salads has increased in recent years. Kale leaves may be harvested at different stages of maturity, resulting in a heterogeneity that may be detrimental to fresh-cut salad quality and shelf-life. Changes in composition and visual parameters were investigated in fresh-cut kale leaves (var. Lacinato) harvested at three maturity stages used commercially and based on leaf position and size (immature, mature, overmature), two temperatures (0 and 5 degrees C) and five periods of storage (0, 14, 21, and 28d; up to 42d at 0 degrees C). Product was cut manually into 2cm strips, washed in chlorinated water, manually centrifuged and packaged in unsealed LDPE bags. Total chlorophyll content decreased during storage, with the lowest concentrations found in pieces from ‘overmature’ leaves at 5 degrees C, while the total carotenoid content did not vary among the conditions studied. Ammonia content, an indicator of membrane degradation and senescence, remained low for pieces from all maturity stages stored at 0 degrees C up to 42 days, was intermediate in immature cut leaves at 5 degrees C, and increased dramatically in pieces from mature and overmature leaves at 5 degrees C between 21 and 28 days. Objective color (L*, a* and b* values) as well as marketability indicators (off-odors, overall visual quality, yellowing, decay, cut-end browning) exhibited significant differences in response to the postharvest conditions studied. In general, the loss of composition and visual quality of fresh-cut kale leaves increased with increasing temperature, days of storage, and leaf maturity.

Low intensity postharvest lighting improves quality and shelf life of fresh-cut lettuce

Woltering, E.J. (Wageningen University and Research Centre, Food & Biobased Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands and Wageningen University, Horticulture & Product Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands)Witkowska, I.M. (Wageningen University, Horticulture & Product Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands)Schouten, R.(Wageningen University, Horticulture & Product Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands)Harbinson, J. (Wageningen University, Horticulture & Product Physiology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands)
Fresh-cut butterhead and iceberg lettuce was stored in darkness and under low light conditions (approximately 5 µmol m-2 s-1 PAR) provided by either fluorescent tubes, red, blue or green LEDs. Low light conditions considerably improved quality compared to storage in darkness; lighting delayed cut-edge browning and greatly prolonged the shelf life. In dark stored samples a rapid depletion of chlorophyll, carotenoids, ascorbic acid and carbohydrates was observed. In lit samples, chlorophyll and carotenoids decreased in a similar fashion as in dark stored samples but ascorbic acid levels were preserved. In lit butterhead samples total carbohydrates increased over 10 times the initial levels. In iceberg samples, the decrease in total carbohydrates observed in the dark was greatly delayed by light. The applied light levels of approximately 5 µmol m-2 s-1 PAR are well below the light compensation point of lettuce, indicating that the preservation of carbohydrates is not through photosynthetic sugar production. Measurements of photosynthetic activity confirmed that there was no net photosynthesis in lit samples. The preservation of sugar and ascorbic acid and the prolonged shelf life occurred independent of the applied light source (fluorescence tubes, LEDs). The prolonged shelf life of low light-treated samples is presumably due to the higher levels of sugar and ascorbate that may act as antioxidants, may preserve membrane integrity and may provide sufficient respiratory substrate to prevent ATP depletion. We hypothesize that, under low light conditions, sugars may be produced through the processing of chloroplast degradation products in the glyoxysome, subsequent production of malate and oxaloacetate and production of glucose through reversal of the glycolysis pathway (gluconeogenesis). The use of light as a novel sustainable postharvest technology is discussed.

Minimally processed long-storage Mediterranean tomato: A novel product from traditional crops in the agrifood industry

Cristina Patanè (CNR-IVALSA, Catania, Italy), Alessandra Pellegrino(CNR-IVALSA, Catania, Italy)Laura Siracusa (CNR-ICB, Catania, Italy), Giuseppe Ruberto (CNR-ICB, Catania, Italy), Valeria Rizzo (Di3A, University of Catania, Italy), Francesco Giuffrida (Di3A, University of Catania, Italy)

The Mediterranean “long-storage” tomato, which allows an extended shelf life due to the textural properties, provides a delightful product that combines a good taste with excellent nutritional properties. Due to the high drought tolerance of the plant, long-storage tomato is traditionally cultivated under no water supply, indicating an interesting genetic source in breeding programs for water stress resistance in both fresh and processing tomatoes. Recent studies have been indicating the feasibility to obtain a new minimally processed product from local landraces of long-storage tomato, due to the low water content of fruits and the high content in bioactive constituents, including vitamin C, carotenoids, and phenols. A study has been conducted with the aim of assessing the quality of fresh-cut long-storage tomato during storage at 4 degree C as compared to a commercial cultivar of cherry tomato. All fruits were 10 min-disinfected in a sodium hypochlorite solution before cut. Long-storage tomato exhibited higher quality levels than commercial tomato throughout 14 days of storage, e.g. in terms of phenols (>80 mg/100 g), soluble solids (>7°Brix), pH (<4), and antioxidant activity (>80% inhibition). One-hour presoaking of pre-cut fruits in calcium chloride solution, relative to presoaking in citric acid solution, resulted in greater quality levels of fruits during storage. Soaking either in calcium chloride or citric acid solution was beneficial for microbial quality, when compared to relative control (soaking in distilled water) but not when compared to the overall control (no soaking after disinfection), where the overall quality of fruits was best.

Model for transpiration rate at water vapour saturated conditions

Pramod Mahajan, Guido Rux, Oluwafemi Caleb, Manfred Linke, Werner Herppich, Martin GeyerDepartment of Horticultural Engineering, Leibniz Institute for Agricultural Engineering, Potsdam Bornim, Germany

Water vapour saturation is commonly observed in the packaged fresh produce. The reason is moisture evolved from the product and insufficient water vapour permeability of packaging material. Under such conditions, even minor temperature fluctuations result in condensation inside the package causing sliminess, decay, enhancement of microbial growth, and browning of produce surface. This study investigated the moisture loss behaviour of mushroom, strawberry and tomato under 100% relative humidity saturated storage environments. Mass and surface temperature of each product was continuously measured using electronic balance and infrared thermometer connected to the data logger. A perforated plastic sphere filled with water storing polyacrylamide granulates was used as dummy evaporation sphere. Despite water vapour saturation, mushrooms, strawberries and tomatoes transpired at rates of 712, 122 and 18 mg of H2O kg-1 h-1, respectively. Respiratory heat production led to produce surfaces temperatures higher than that of the surrounding air. In turn, this resulted in an outward directed water vapour gradient. This was confirmed with no mass loss from the evaporation sphere. Interestingly, when mushroom was exposed to lower humidity (65%), there was rapid increase in mass loss. Consequently, evaporative cooling significantly reduced surface temperature below the surrounding air temperature. A generalised mathematical model was developed to predict mass loss as a function of temperature and relative humidity of storage environment and respiration rate of fresh produce. Application of such model to design modified humidity packaging was demonstrated for the selected fresh produces.

Nutritional Quality of Fresh-cut Products


The sales in fresh-cut (FC) produce is one of the major growing segments in food retail establishments and some are the main components of a healthy diet. Fresh-cut fruits contain many nutritional components such as carbohydrates, fats, proteins, fiber, minerals, organic acids, and some pigments, vitamins and antioxidants. Especially antioxidants have been associated with the prevention of diseases such as cancer and cardiovascular disease, among others. FC fruits are relatively low in calories and fat, they have no cholesterol and relatively low in sodium and high in potassium. The nutritional value of fruits-cut fruits depends on their composition, which shows a wide range of variation depending on the species, cultivar and maturity stage. Different metabolites are present FC fruits and are more available than that of whole fruits. After ingestion they are released absorbed and have different physiological roles in the body, being some of particular interest. Pre-harvest and postharvest treatments affects the nutritional value of these fruits. During maturation, storage and marketing, some biochemical and physiological changes and microbiological growth occurs leading in nutritional loss. The most important techniques used to prevent FC fruits disorders and the possible mode of action, will be discussed. The effects of these compounds on human nutrition and health are highlighted, exploring the mechanisms involved in their protective actions. The most important presentations of FC fruits available in the market, processing techniques and packaging used to prevent nutritional losses will be present.

Optimizing minimal processing and shelf life conditions to better preserve Chinese parsley quality

Hangjun Chen Qiang Han, Honglei Mu, Yongjun Zhou, Xiangjun Fang, Haiyan Gao* Key Laboratory of Fruits and Vegetabl es Postharvest and Processing Technology Research of Zhejiang Province, Food Science Institute, Zhejiang Academy of Agricultural Science, Hangzhou, Zhejiang, 310021, China

Chinese parsley (Coriandrum sativum L.) is one of the oldest aromatic vegetables which are used for flavoring. However, it could be easily lost its original nutrition and flavor, because of mechanical wounding and improper storage methods. Minimally processed vegetables (MPV) could mostly satisfy the new demand of vegetable consumption because of its nutrition, fresh, convenient and no pollution. Therefore, it was very important to find out the suitable minimal processing and preservation technology for Chinese parsley.

In this study, the suitable storage temperature for Chinese parsley was explored, the appropriate cleaning preservative was screened, and the suitable initial gas composition for modified atmosphere packaging was also to be screened. The main results are as follows:(1) The influence of different storage temperatures on the quality of the MPV Chinese parsley has been studied. The results indicated that reducing the storage temperatures appropriately favored Chinese parsley to maintaining the quality of MPV. (2)The impact of storage quality of MPV coriander cleaned with different preservatives (NaClO, steady-state ClO2 and sodium butylparaben) has been studied. It was indicated that preservative cleaning Chinese parsley helped to maintain the higher sensory scores and lower weight loss. (3)The gas composition for modified atmosphere packaging of Chinese parsley was explored, based on the effective on storage quality and regulation on senescence process. The results show that the gas composition of 15% O2 + 3% CO2 + 82% N2 could be able to participate in the regulation of reactive oxygen metabolism coriander.

Organic acids produced by lactic acid bacteria (Leuconostoc sp.) are related to sensorial quality decrease in modified atmosphere packed fresh-cut iceberg lettuce

Paillart, M.J.M. (Wageningen UR - Food & Biobased Research);Van der Vossen, J.M.B.M. (TNO); Woltering E.J. (Wageningen UR - Food & Biobased Research)

The shelf life of fresh-cut lettuce packed in modified atmosphere (MA) packaging is generally determined by its “overall visual quality (OVQ)” being a measure of its general appearance based on colour and shape criteria. Additionally to OVQ, development of off-flavour and acid off-smell limits the consumer’s acceptance of such products. Concomitant with these changes in organoleptic properties, there is a rapidly developing microbial population inside MAP, dominated by lactic acid bacteria species. Few studies have investigated the possible interactions between the growth of this specific bacteria population and the sensorial quality decay of fresh-cut lettuce. We studied the bacterial population dynamics of active MA packed fresh-cut lettuce and studied the effect of bacteria-produced metabolites (lactic acid and acetic acid) on lettuce quality aspects. Within 3 days of packaging, the oxygen concentration in the package was near zero and this greatly stimulated the development of lactic acid bacteria, in particular Leuconostoc and Lactococcus species. Leuconostoc, when cultivated on lettuce-enriched medium, was found to produce both acetic and lactic acids. Low concentrations, of acetic and lactic acids were determined in MA packed lettuce after 5 days of storage at 7 degrees C. Fresh-cut lettuce treated with comparable low amounts of acetic and lactic acid showed strong quality decay. This was reflected in rapid discoloration and increases in tissue electrolyte leakage (indication cell damage). The experiments show that organic acids produced by lactic acid bacteria under anaerobic conditions affect both off-flavour production and sensorial quality decay in fresh-cut lettuce.

Overall Quality of Minimally Processed Pea Seeds

Elena Collado1, Francisco Artés-Hernández1,2, Laura Navarro1, Francisco Artés1,2, Encarna Aguayo1,2, Juan Fernández1,3 and Perla A. Gómez1*1 Institute of Plant Biotechnology. Technical University of Cartagena. Campus Muralla del Mar. 30202. Cartagena, Murcia, Spain.2 Postharvest and Refrigeration Group. Department of Food Engineering. Technical University of Cartagena. Paseo Alfonso XIII, 48. 30203. Cartagena, Murcia, Spain.3 Department of Horticulture. Technical University of Cartagena. P. Alfonso XIII, 48, 30203. Cartagena, Murcia, Spain.

Peas (Pisum sativum L. var. saccharatum) are an important source of protein, carbohydrates, vitamins and minerals. Pods are harvested before physiological maturity and stored at temperatures near 0 degrees C. Due to their very high respiration rate, and even when classified as non-climacteric product, loss of quality is fast. Most studies conducted on fresh peas have dealt with the fresh pod but very little information is available on the optimum storage conditions of immature pea seeds, which are well adapted to be prepared as a minimally processed product. The effects of passive modified atmosphere packaging and sanitation with chlorine (100 ppm, pH 6.5) or alternatively with acidified sodium chlorite (300 ppm, pH 1.8) on overall quality of fresh pea seeds (var. ‘Lincoln’) were assessed during shelf life at 1 and 4 degrees C. After 12 d atmospheres within packages were 8 kPa CO2/12 kPa O2 and 11 kPa CO2/10 kPa O2 at 1 and 4 degrees C respectively. Spoilage microbial growth (mesophilic, enterobacteria, psychrotrophic and yeast and mould) were around 2 log CFU g-1 and 3 log CFU g-1 at 1 degree C and 4 degrees C respectively. However, enterobacteria growth was drastically reduced at 1 degree C independently of the disinfectant used. Colour, firmness and sensory quality were acceptable, with best quality at 1 degree C. Low temperature storage allowed obtaining a high quality product after 12 d, being acidified sodium chlorite a good alternative to chlorine. However, more research is needed to study its effects in other quality parameters.

Physiology and biochemistry of aroma and off-odors in fresh-cut products

Charles F. Forney (Agriculture and Agri-Food Canada, Atlantic Food and Horticulture Research Centre, Kentville, NS)
The aroma of fresh-cut produce contributes to product quality and can determine consumer acceptability. Aroma is determined by the composition of volatile compounds released by the product, which is dependent on the product type, genetics, maturity and postharvest handling. The great diversity of fruits and vegetables provides a wide array of volatile chemistries that contribute to the unique aroma of each commodity. The aroma volatile content of the product at the time of cutting has a major impact on product aroma. Therefore, product maturity, or ripeness in the case of fruit, should be optimized to provide desirable aroma. In addition to volatile compounds produced by the intact commodity, secondary volatile compounds may be produced when products are cut or processed. Postharvest handling, including packaging and temperature management, also impact aroma. Aroma of fresh-cut produce changes as a result of diffusional and metabolic processes during marketing. Cutting removes natural diffusional barriers and interaction of volatiles with packaging materials can preserve aroma or hasten its loss. Atmosphere modification within packages also alters volatile metabolism. Atmosphere compositions low in oxygen and/or high in carbon dioxide can induce anaerobic metabolism, which may result in the production of off-odors. The introduction of precursors of aroma volatiles to fresh-cut produce has the potential to stimulate volatile production of fresh-cut produce and enhance product aroma. The dynamic nature of aroma presents a challenge to design postharvest systems to optimize product aroma and flavor.

Postharvest performance of fresh-cut 'Bing Bang' nectarine as affected by passive atmosphere packaging

Sortino G. (Department of Agricultural and Forest Sciences, University of Palermo), Allegra A. (Department of Agricultural and Forest Sciences, University of Palermo)Gallotta A. (Department of Soil, Plant and Food Sciences, University of Bari)Inglese P. (Department of Agricultural and Forest Sciences, University of Palermo).

Suitability to minimal processing of cv. 'Big Bang' was evaluated by storage fresh-cut slices for 12 days at 5 degrees C in a passive atmosphere, using rigid bi-oriented polystyrene bags (after washing, peeling and slicing). At each stage of storage (0, 2, 5, 9, 12 days after cut), appearance score, weight, color, firmness score, respiration rate, soluble solids, acidity and phenols were measured. Nectarine fresh cut stored at 5 degrees C under passive atmosphere, without chemical treatment, extended their shelf life. Fresh-cut slices fully retained their characteristics up to 5 days of storage. Weight, color, firmness score, soluble solids, acidity and phenols significantly decreased while appearance score did not change until 9 days of storage. The results have shown the ‘Big Bang’ nectarine cultivar, already appreciated for consumption as fresh fruit, was particularly suitable for fresh-cut production.This study may be a further contribution to the selection of nectarine cultivars to be processed as fresh-cut product not only on physiological parameters but also on the basis sensory data.

Preharvest factors and fresh-cut quality of leafy vegetables

Mabel Gil (CEBAS-CSIC, Murcia, Spain)

Quality losses concerns of fresh-cut leafy vegetables are mainly due to 1) browning of cut edges due to tissue disruption and oxidative processes, 2) increased respiration and metabolic reactions with development of off-odours and 3) tissue softening. The quality and postharvest shelf life of fresh-cut leafy vegetables can be affected by a range of pre-harvest factors. The potential shelf-life of the fresh-cut product through the evaluation of the raw material and the processed product will be revised for the selection of cultivars with lower response for cutting. Environmental conditions such as temperature, RH, light intensity and rainfall influences cultivation in different production areas and growing cycles. Agricultural practices particularly irrigation regimens that have a direct effect on the quality of leafy vegetables. On the other hand, fertilizers and cultivation systems will be revised as growing systems for baby leaves. Maturity stage also affects the shelf-life of fresh-cut leafy vegetables. Over-mature lettuce has a shorter shelf-life of the fresh-cut product because of the higher browning potential versus fermentation in the immature stage. Differences in the quality related to the turgid and the susceptible to mechanical damage of the leafy vegetables at different harvest time should be presented. Postharvest handling conditions particularly relative humidity will be also examined as critical conditions to maintain the quality of fresh-cut leafy vegetables. The beneficial effect of different cooling systems such as the use of cold rooms, forced-air cooling, vacuum cooling and hydro vacuum-cooling will be revised.

Quality Changes of Fresh-cut Figs in Relation to Ripeness Stage, Temperature and Controlled Atmospheres

Gyunghoon Hong (Dept. Plant Sciences, UC Davis, Davis, CA 95616), Carlos Crisosto (Dept. Plant Sciences, UC Davis, Davis, CA 95616), and Marita Cantwell (Dept. Plant Sciences, UC Davis, Davis, CA 95616)

The performance of fresh-cut figs was evaluated for 2 cultivars at 2 stages of ripeness (commercial and full ripe). Texture, but not external color, was a consistent indicator of ripeness. Fresh-cut figs (maroon-skin Brown Turkey and yellow-green skin Sierra cultivars) were prepared from sanitized fruit, halved with a stainless steel knife, and stored in plastic clamshells in air at 0 or 5 degrees C or controlled atmospheres (3%O2 + 6, 12 or 18%CO2) at 5 degrees C. Cut pieces retained excellent quality for 6 days under all conditions. After 9 and 12 days, best quality was obtained in air at 0 degrees C and in CA at 5 degrees C with 12 or 18%CO2, but these atmospheres resulted in increased ethanol and acetaldehyde concentrations. Sugars decreased in ‘Brown Turkey’ but not in ‘Sierra’ fruit and were different between ripeness stages. Respiration of fresh-cut figs was similar to that of intact fruits (4-7 and 8-10 µL CO2/g-h at 0 and 5 degrees C, respectively). Ethylene production was similar between ripeness stages, but different between cultivars. Loss of visual quality was not associated with discoloration but with microbial growth on the cut surfaces similar to that on the external surface of intact fruits. This was due mostly to molds and CO2 atmospheres retarded fungal growth. Temperature control was much more important than controlled atmospheres for fresh-cut fig shelf-life. Shelf-life was little affected by ripeness stage but full ripe fruit had higher sugar content. Figs performed well as fresh-cut products and could add flavor and diversity to cut fruit trays.

Quality Changes of Green Vegetables Smoothies During Shelf Life

Noelia Castillejo1, Ginés Benito Martínez-Hernández1,2, Perla A. Gómez2, Francisco Artés1,2, Encarna Aguayo1,2, Carmen Sánchez–Álvarez3 and Francisco Artés-Hernández1,21 Postharvest and Refrigeration Group. Department of Food Engineering. Technical University of Cartagena. Paseo Alfonso XIII, 48. 30203. Cartagena, Murcia, Spain.2 Institute of Plant Biotechnology. Technical University of Cartagena. Campus Muralla del Mar. 30202. Cartagena, Murcia, Spain.3 Nutrition Department. Hospital General Universitario Reina Sofía, Avda. Intendente Jorge Palacios, 1, 30003. Murcia. Spain.

The health-promoting benefits of the Mediterranean diet are related to fruits and vegetables intake, which are an important source of phytochemicals such phenolics, carotenoids and vitamin C among others. Smoothies are an excellent solution to ingest these health-promoting compounds in an easy way by increasing fruit and vegetables consumption. Two different green vegetables smoothies V1 (accounting tomato, carrot and spinach the 90 % of the composition) and V2 (90 % of cucumber and broccoli), were lightly processed with a mild heat treatment. Physicochemical properties, sensory analyses, and nutritional/bioactive (vitamin C, phenolics, antioxidant capacity, carotenoids and chlorophylls) and microbial quality of the smoothies were studied during 7 days at 5 or 20 degrees C. Generally, soluble solids content, pH and titratable acidity did not greatly changed after 7 days of storage at both temperatures. V2 smoothie registered lower microbial growth after 7 days with better sensory scores regarding V1. Initial total phenolic contents (28-30 mg gallic acid equivalent 100 g-1 fw) of both smoothies were well preserved during shelf life even at 20 degrees C with changes below 19%. Initial vitamin C contents (15-30 mg kg-1 fw) were remained quite stable throughout storage at 5 degrees C although storage at 20 degrees C induced reductions of 30-40 % after 7 days. Conclusively, the bioactive/nutritive properties of green vegetable smoothies did not greatly changed during refrigerated storage achieving V1 smoothie the best microbial and sensory qualities.

Sensory quality of fresh-cut products

Anne Plotto (USDA, ARS) Jinhe Bai (USDA, ARS) Jan Narciso (USDA, ARS - retired) Liz Baldwin (USDA, ARS)

Sensory evaluation is primarily used by food companies in product development and prior to marketing. It has been adopted by the horticultural research community as an additional measure of produce quality upon pre- and postharvest treatments. With fresh-cut fruits, maturity of the product at processing time, sanitation, packaging and storage can all affect appearance and flavor. Sensory tests are designed to evaluate processing and fruit variables. Example of recent research at the USDA-ARS will be given: edible coatings on fresh-cut zucchinis, active packaging, effect of chilling injury on sensitive commodities, maturity and storage studies, etc. In some cases, when an unexpected sensory quality was observed due to a specific treatment, additional analytical measurements were warranted to understand the underlying effect of such treatment.

Shelf-life of fresh-cut tomato in relation to cut and fruit typologies

Francesco Giuffrida (Di3A, University of Catania, Italy), Carla Cassaniti (Di3A, University of Catania, Italy), Letizia Inserra (Di3A, University of Catania, Italy), Angelo Malvuccio (Di3A, University of Catania, Italy), Cristina Restuccia (Di3A, University of Catania, Italy), Cristina Patanè (CCNR-IVALSA, Catania, Italy), Cherubino Leonardi (Di3A, University of Catania, Italy)

Three typologies of tomato (round cv. ‘Ventero’, salad cv. ‘Marmalindo’, elongated cv. ‘Sir Elyan’) were minimally processed in slices or wedges and packaged in polypropylene trays (500 g each). Slices (7 mm thickness) were obtained cutting fruits perpendicularly to the main axis. For wedges, fruits were divided into 4 or 8 parts (depend on fruit diameter). At the beginning (day 0), and after 3, 6 and 9 days of storage at 4 degrees C, quality attributes (total bacterial load, colour, pericarp firmness, soluble solids, titratable acidity, dry matter, antioxidant activity, content of vitamin C, lycopene and ß-carotene) were evaluated. Concentration of CO2 and O2 into the tray were also measured. Significant interactions between fruit typology, cut and storage were observed in few quality characteristics. Fruit dry matter was highest at day 6 in slices and edges of ‘Marmalindo’, at day 3 in edges and at days 6 and 9 in slices of ‘Sir Elyan’, whereas slight differences were observed in ‘Ventero’. The same behavior was observed in soluble solids. In general, shelf-life of fresh-cut tomato was more influenced by fruit typology than cut type. Firmness in round tomato did not change with days, but decreased in salad and elongated tomato (-45% and -30% from 0 to 9 days for ‘Marmalindo’ and ‘Sir Elyan’, respectively). The highest antioxidant activity was found on ‘Ventero’ cultivar (14.4 µmol TE/g DW) and in fruit wedges (13.4 µmol TE/g DW). Significant differences were also observed in the content of vitamin C, lycopene and ß-carotene.

The biological role of glucosinolates and isothiocyanates in rucola, and the effects on sensory quality traits

Luke Bell (University of Reading)Natasha Spadafora (Cardiff University)Lisa Methven (University of Reading)Carsten Müller (Cardiff University)Maria Jose Oruna-Concha (University of Reading)Hilary Rogers (Cardiff University)Carol Wagstaff (University of Reading)

Rucola (rocket; Eruca & Diplotaxis spp.) are leafy salad crops that contain glucosinolates (GSLs) and various other interesting phytochemicals. GSLs and their hydrolysis breakdown products are utilised in plant defense against pathogens and pests, but are also known to be the cause of strong, pungent, and bitter tastes and aromas. Some of these compounds are very efficacious at deterring pests and disease, but are also repellant to many consumers. Most focus on quality has previously been given to visual traits – in our work we have focused on quality phytochemical traits, such as maximizing heath beneficial compounds (GSLs, isothiocyanates (ITCs), and flavonols) but also assessing how these compounds affect sensory attributes, and in turn, the ‘quality’ of the eating experience. Six accessions of germplasm rucola and one commercial variety were selected for assessment of such quality traits to determine their potential for introduction into plant breeding programs. GSLs and flavonols were analysed by LC-MS, volatile compounds by GC-MS, and sugars by capillary electrophoresis. The cultivars were also tested in controlled sensory evaluations by a panel of ten, highly trained sensory analysts. Data from sensory and technical analyses were combined using Principal Component Analysis (PCA) to determine significant correlations between sensory traits and chemical compounds. It was found that a large amount of variation exists between cultivars of rocket, and the levels of bitterness, pungency, and sweetness are largely due to differences in GSL/ITC profiles and the ratio of these compounds with sugars.

Tips and procedures to evaluate quality of stored and minimally processed fruits and vegetable using sensory testing

Anne Plotto (USDA-ARS, Fort Pierce, FL), Jinhe Bai (USDA-ARS, Fort Pierce, FL), Elizabeth Baldwin (USDA-ARS. Fort Pierce, FL), Jan Narciso (USDA-ARS, Fort Pierce FL), Maria-Teresa Blanco-Diaz (IFAPA, Almeria, Spain), Libin Wang (Nanjing Agric. Univ., Nanjing, China)

Sensory evaluation is primarily used by food companies in product development and prior to marketing. It has also been adopted by the horticultural research community as an additional measure of produce quality upon pre- and postharvest treatments. With fresh-cut fruits, maturity of the product at processing time, sanitation, packaging and storage can all affect appearance and flavor. Sensory tests are designed to evaluate processing and fruit variables. Example of recent research at the USDA-ARS will be given: maturity and storage effect on flavor of new blueberry cultivars, postharvest heat treatments on stored grapefruit, edible coatings on fresh-cut zucchinis, etc. In some cases, when an unexpected sensory quality was observed due to a specific treatment, additional analytical measurements were warranted to understand the underlying effect of such treatment.

Use of Digital Image Processing for Evaluation of Translucency in Fresh Cut ‘PÉROLA’ Pineapple Coated with Biofilms

Renato Pereira Lima (CCA/UFPB, BRAZIL), Silvanda de Melo Silva* (PPGA/CCA/UFPB, BRAZIL), Renato Lima Dantas (UACTA/UFCG), Ana Lima Dantas (PPGA/CCA/UFPB), Alex Sandro Bezerra de Sousa (CCA/UFPB), Walter Esfrain Pereira (PPGA/CCA/UFPB), Rejane Maria Nunes Mendonça (PPGA/CCA/UFPB)

The translucency in 'Perola' pineapple, characterized by water-soaking areas in the flesh, intensifies during storage of fresh cut product causing loss of quality. The evaluation of the pineapple translucency has been performed by subjective scales, grading the evolution of the translucent area of the cross section of fruit. However, the digital image processing, using free software like ImageJ®, can allow the extraction of more precise information on the translucency considering, for instance, the tone of image coloration, the areas in which it occurs, and the pixels in the RGB channels. Therefore, this study proposed a method for evaluation of translucency in fresh cut ‘Pérola´ pineapple using the digital image processing (DIP). 'Perola' pineapple was cut in 10 mm-thick slices, which were coated with cassava starch (3%), cassava starch (3%) + fennel oil (0.025%), cassava starch (2%) + sodium alginate (1%) + fennel oil (0.035%), cassava starch (3%) + glycerol (1%) + ascorbic acid (0.5%), and stored for 12 days at 5 degrees C and 90% RH. The DIP was developed using variations of hue angle, saturation, and brightness by the ImageJ® software. The correlation of the subjective evaluation with the DIP was highly significant (r = 0.90 **), i.e., it was efficient at determining the translucency in ‘Perola’ pineapple slices. A predictor model was developed using partial least squares analysis. This model, which included the coloration of the slices and the RGB values, had a high linear coefficient of determination (r = 0.96 significance).

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