Cryoprotectants improve physical and chemical properties of frozen blue crab meat (Callinectes sapidus)

The storage stability of cryogenically frozen crab meat treated with cryoprotectants was compared with pasteurised and water-treated frozen samples to determine changes in physical and chemical properties. Commercially processed, hand-picked blue crab meat was treated with solutions of polydextrose, sucrose + sorbitol/sodium tripolyphosphate or water, vacuum packaged, and cryogenically frozen prior to storage at ?29°C. All treatments were compared with an untreated reference control stored at ?65°C and a pasteurised sample stored at 1.1°C. Samples were evaluated for physical and chemical changes at 4-week intervals over 32 weeks of storage. Cryoprotectants improved oxidative stability, drip loss, expressible moisture, texture, and colour compared to untreated reference and pasteurised samples.     

Effects of short‐term N2 treatment on quality and antioxidant ability of loquat fruit during cold storage

BACKGROUND: Loquat fruit is susceptible to microbial decay and quality deterioration during postharvest distribution. In this study, in a search for effective alternatives to methods currently used for quality maintenance, the effects of short‐term pre‐storage N₂ treatment on the quality and antioxidant ability of loquat fruit were investigated. RESULTS: Loquat fruits were exposed to 100% N₂ for 6 h at 20 °C and then stored at 5 °C for 35 days. Short‐term N₂ treatment significantly delayed the increase in fruit decay rate and decreases in total soluble solid and titratable acidity contents, thereby maintaining better eating quality and extending the storage life of fruits. It also markedly delayed increases in membrane permeability, malondialdehyde content and superoxide anion production rate. In addition, N₂‐treated fruits exhibited significantly higher superoxide dismutase and catalase activities and lower lipoxygenase activity than control fruits. CONCLUSION: Short‐term pre‐storage N₂ treatment effectively reduced fruit decay and maintained quality in loquat fruits during cold storage. The reduction in fruit decay and quality deterioration by the treatment was correlated with enhanced antioxidant ability and reduced lipid peroxidation. Copyright © 2009 Society of Chemical Industry     

Effects of Processing and Storage on the Water-Soluble Vitamin Content of Human Milk

Effects of four heat treatments (62.5°C, 30 min; 72°C, 15 sec; 88°C, 5 sec; and 100°C, 5 min) and frozen storage (?20°C, 4 wk) on water-soluble vitamin content of composite samples of mature human milk were determined. No changes in riboflavin, biotin, and total pantothenic acid content were observed after any of the treatments. Heating at 100°C for 5 min decreased thiamin, vitamin B₁₂, and vitamin C contents. Vitamin Bs content was reduced by heating at 88°C and 100°C. Free folate was not affected by heating while total folate concentration was decreased similarly by all heat treatments. During frozen storage at ?20°C, niacin and free pantothenic acid concentrations were reduced; riboflavin, vitamin Bs, biotin, total pantothenic acid, vitamin C, and vitamin B₁₂ were unaffected; while measurable thiamin and free folate concentrations increased. Overall, the two lower temperature treatments were less detrimental to the water-soluble vitamins in human milk.     

CaCl_2对采后不同成熟度冬枣抗氧化及细胞壁代谢的影响

为探讨CaCl_2处理对不同成熟度冬枣(Zizyphus Jujuba Mill.cv.Dongzao)抗氧化能力及细胞壁代谢的影响,试验采用1%和2%CaCl_2浸泡处理白熟期(WM)和半红期(HM)冬枣果实,以水处理为对照,测定20±2℃贮藏过程中果实硬度、过氧化氢(H_2O_2)、丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化物酶(CAT)、抗坏血酸(As A)、还原型谷胱甘肽(GSH)、多聚半乳糖醛酸酶(PG)以及细胞壁组分(水溶性果胶(WSP)、离子结合果胶(ISP)和共价结合果胶(CSP))变化。结果表明,在贮藏过程中1%和2%CaCl_2处理可显著延缓WM和HM期果实硬度下降,抑制H_2O_2和MDA积累,维持较高水平的SOD和CAT活性以及As A和GSH含量,同时,降低PG活性以及WSP和ISP含量,增加CSP含量,其中1%CaCl_2处理对HM期果实作用效果最显著,通过提高其抗氧化活性和抑制细胞壁降解过程,使其在贮藏期间保持较好的果实品质。     

Storage stability of a tropical fruit (cashew apple,acerola, papaya,guava and passion fruit) mixed nectar added caffeine

Nectars are formulated beverages with a fruit juice or pulp as its main component. A blend of fruits can also be used, with the advantage of combining sensory and nutritional properties of different fruits. The beverages may be added with some energetic component, as caffeine, known by its stimulating effect on central nervous system. The objective of this study was to develop mixed nectar of cashew apple, papaya, guava, acerola fruit and passion fruit added caffeine. The beverage was prepared with 35% juice blend and 10% sugar, added with 100 mg of caffeine L^?1 and 60 mg of sodium metabisulfite (SO₂) L^?1 and 500 mg of sodium benzoate L^?1 as preservatives, packed in cleaned pasteurised bottles and heat processed at 90 °C for 30 s. Physicochemical, microbiological and sensory analyses of the beverage were performed initially (time zero) and during 6 months of storage at room temperature (about 25 °C). The products were microbiologically stable during storage. The vitamin C content decreased significantly throughout storage time, although it has remained relatively high. The product presented good sensory acceptance, which suggests its potential for market.     

Non‐freezing points below zero induce low‐temperature breakdown of kiwifruit at harvest

To induce low‐temperature breakdown (LTB) at harvest, a post‐storage disorder of kiwifruit, kiwifruit were exposed to ?2 °C (a temperature determined to be above the freezing point), for 0 (control), 6, 12, 18, 24, 30, 36 and 42 h, followed by 5 days at 20 °C. Kiwifruit were also stored at ?0.5 °C for 16 and 24 weeks plus 5 days at 20 °C. LTB incidence and severity were measured on the cut surfaces following slicing at the upper, middle and lower parts of each fruit subjected to ?2 °C, whereas in stored fruit LTB incidence was measured following slicing at the middle part. Electrolyte leakage (ELL) was also determined. Exposure of fruit to ?2 °C resulted in induction of LTB incidence and severity, which increased with the duration of exposure, particularly, on the upper fruit part. Maximum ELL during exposure at ?2 °C for 36 h or during storage at ?0.5 °C for 16 weeks was as high as 50% of that of the frozen fruit. Fruit exposed to ?2 °C or stored at ?0.5 °C had similar LTB symptoms but both differed from those observed in frozen fruit. LTB of fruit stored at ?0.5 °C for 24 weeks was 27% and corresponded to LTB induced at harvest by exposure at ?2 °C for 24 h. The results of this study confirm that LTB is inducible by low but not freezing temperatures at harvest and therefore it might be considered as the physiological basis towards the development of an LTB incidence index for harvested kiwifruit. Copyright © 2006 Society of Chemical Industry     

The effects of fruit maturation,delayed storage and ethylene treatment on the incidence of low‐temperature breakdown of ‘Hayward’ kiwifruit

BACKGROUND: Low‐temperature breakdown (LTB), a disorder inducing quality loss, during and after cold storage of ‘Hayward’ kiwifruit was investigated. Harvested kiwifruits during fruit maturation or after delayed storage (DS) at 20 °C for 0, 1, 2, 3 and 4 weeks and 1 µL L^?1 ethylene treatment for 24 h were stored at ? 0.5 °C for 24 weeks and additional ripening at 20 °C for 5 days. Fruit quality indices and LTB incidence and severity were determined before and after treatments. RESULTS: Harvested fruits ripened during maturation, DS and after ethylene treatment. After storage and shelf life, fruits of all treatments were at complete ripening stage. LTB incidence of early harvested fruits was high, while that of fruits of the mid (third) and late harvests was low. Fruits of the third harvest date showed progressively increased LTB incidence with increasing duration of DS to as high as 95–100% after 4 weeks. Ethylene‐treated fruits showed a comparable increase in LTB to that corresponding to 2–3 weeks of DS. CONCLUSION: In contrast to fruit maturation, postharvest (after harvest and before storage) DS at non‐chilling temperature and ethylene treatment advanced the ripening of ‘Hayward’ kiwifruit and resulted in increased LTB incidence. Copyright © 2012 Society of Chemical Industry     

Effect of environmental factors [air and UV-C irradiation] on some fresh fruit juices

The present study was carried out to evaluate the effect of environmental factors (air and UV-C irradiation) on various common fruits juices (lemon, orange, papaya and grape). Total phenolics, total ascorbic acid (AA) content and antioxidant capability were determined in atmospheric air oxidation on fresh fruit juices, and the effect of UV-C irradiation on AA was investigated in both fresh fruit juices and commercial AA using RP-HPLC. The total phenolics content was found to be 92.46?±?1.5, 41.53?±?2.1, 138.56?±?2.3 and 110.54?±?3.9?mg/100?ml of lemon, orange, papaya and grape juices, respectively. DPPH radical–scavenging activity of the fresh juices was 94.53?±?3.1, 82.36?±?2.2, 94.65?±?3.5 and 90.74?±?2.6 percentage, whereas the 1-day-old fruit juices showed reduced scavenging activity when compared to fresh juices. Total phenolic (TP) and DPPH-scavenging activity were significantly decreased in the mean at P?<?0.05 level. Ascorbic acid (vitamin C) content of fresh fruit juices was determined through RP-HPLC; fruit juices that were kept in open container for 24 hrs and that were treated with UV irradiation have shown a decrease in AA content, when compared with control fresh juice samples. AA degradation increased with high significant differences at P?<?0.001 level, with the increase in oxidation time in atmospheric air and UV-C radiation.     

Original article: The effect of freezing at −18 °C and −70 °C with and without ascorbic acid on the stability of antioxidant in extracts of apple and orange fruits

The influence of low temperature and storage time on the antioxidant capacity of standard solutions and apple and orange extracts was evaluated. In addition, the effects of ascorbic acid (AA) addition to the fruit extracts in terms of antioxidant capacity, AA content and soluble and hydrolyzable polyphenol contents were also analysed. Polyphenol contents in both apple and orange extracts were stable during storage period, which reflected also in the antioxidant capacity stability. Freezing at ?18 °C did not result in different retention rates for polyphenols, AA and antioxidant capacity when compared to freezing at ?70 °C. However, vitamin C content in orange juice, without AA addition, slightly increased along the experimental period (10 days). Thus, this study shows that it may not be necessary to measure the antioxidant capacity immediately after the preparation of fruit extracts or antioxidant standard solutions.     

Fluctuations in the Levels of Antioxidant Compounds and Antioxidant Capacity of Ten Small Fruits During One Year of Frozen Storage

The fluctuations in antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl, 2,2´-azinobis (3-ethylbenzthiazoline-6-sulphonic acid), and ferric reducing/antioxidant power assays), total phenol, total flavonoid, and total anthocyanin contents of 10 small fruits (sweet cherries, sour cherries, strawberries, red currants, raspberries, blackberries, hawthorn, cornelian cherries, and red and white grapes) were monitored during storage at ?20°C. After one year in storage, all varieties except hawthorn and white grapes retained equal or slightly greater total phenol content in comparison to the initial values. The total flavonoid and total anthocyanin levels also remained stable or even increased after 12 months in all fruits exept hawthorn and strawberries. Red currants and raspberries exhibited optimal preservation of antioxidant capacity, while hawthorn showed a decrease in the antioxidant capacity during different time points in storage as well as at the end of storage. Analyzed fruits were classified into four main groups based on hierarchical cluster analysis.     

Changes in cuticle compositions and crystal structure of ‘Bingtang’ sweet orange fruits (Citrus sinensis) during storage

Changes in composition and structure of orange cuticle during storage at 4°C or 25°C for 40 days were investigated. The total epicuticular wax content of fruits increased during storage at 4°C for 30 days and then decreased as storage time prolonged to 40 days, while it increased continuously at 25°C for 40 days. The total intracuticular wax content of fruits increased to 9.70 μg cm^?2 stored at 4°C for 10 days and then decreased to 6.74 μg cm^?2 for 40 days. The total intracuticular wax content of fruits was decreased to 5.17 μg cm^?2 stored at 25°C for 10 days and then increased to 10.06 μg cm^?2 for 30 days. Fatty acids were the most abundant component of the epicuticular wax and terpenoids were restricted to the intracuticular wax. Terpenoids were restricted to the intracuticular wax, and their amounts in the fruit stored at 4°C increased continuously during the first 20 days of storage at 4°C and then decreased as storage time increased up to 40 days. Although significant changes were found in the contents of the cutin monomer, their proportions did not change significantly during storage at 4°C or 25°C. Size of wax platelets crystals wax increased during storage of fruits at 4°C up to 30 days; however, the crystals were degraded and decreased as storage prolonged to 40 days. Furthermore, the shape of the fruit cuticle surface wax crystals changed from flattened platelets to small granulelike after storage at 25°C for 20–40 days. The obtained results provide detailed information about the changes in orange cuticle occur during storage at varying temperatures, which may help in preserving the quality of citrus fruits during storage.     

Influence of Postharvest UV-C Hormesis on the Bioactive Components of Tomato during Post-treatment Handling

Mature green tomato fruit exposed to a pre-determined hormetic dose of UV-C (3.7 kJ/m²) and untreated fruit (control) were stored at 13 °C and 95% relative humidity. After 10, 20, and 30 days of storage, fruits were randomly sampled and transferred to room temperature (23 °C) for 7 and 14 days to allow ripening. Edible pericarp was excised from the equatorial region for subsequent analyses of the antioxidant components. Ascorbic acid and total phenolic contents were higher in the UV-treated tomatoes, but UV treatment significantly reduced the lycopene content of the tomatoes. The UV treatment did not affect significantly the antioxidant activity of the hydrophilic extract, expressed as Trolox equivalent. Both storage and ripening period were found to affect positively all the bioactive components of tomato evaluated in this study. The results suggest the possible existence of a window of opportunity for the development of practices based on storage temperature and duration to preserve the beneficial effects expected from UV-C hormesis and to circumvent its negative impact on lycopene synthesis.     

Effect of Plant Extracts on Quality of Khasi Mandarin (Citrus reticulata Blanco) Fruits During Ambient Storage

Khasi mandarin (Citrus reticulata Blanco) fruits were treated with Azadirachta indica, Ocimum sanctum, Aloe barbedensis, carbendazim, A. barbedensis + A. indica, A. barbedensis + O. sanctum, A. barbedensis + carbendazim and control (water). Treated fruits were packed in corrugated fibre boxes and kept for a total period of 28 days at ambient storage (20?±?2 °C and 65?±?5% RH). Prominent pathogen associated with fruit rot was identified as Penicillium brevicompactum. The fruit quality during storage was evaluated in terms of disease severity (per cent disease index), inhibition of spore germination (%) of P. brevicompactum, decay loss (%), juice content retention (%), total soluble solids (%), acidity (%), ascorbic acid content (mg/100 g) and sensory scores. O. sanctum-treated fruits exhibited minimum decay loss (3.33%) up to a total period of 28 days which was even less than carbendazim (10%). O. sanctum was also highly effective in inhibiting spore germination of P. brevicompactum (96.5%). Overall acceptability score (7.33) was also high in O. sanctum-treated fruits as compared with other treatments at the end of the storage period.     

Alginate Coatings Preserve Fruit Quality and Bioactive Compounds during Storage of Sweet Cherry Fruit

Sweet cherry fruits harvested at commercial maturity stage were treated with an edible coating based on sodium alginate at several concentrations (1%, 3% or 5% w/v). The coatings were effective on delaying the evolution of the parameters related to postharvest ripening, such as colour, softening and loss of acidity, and reducing respiration rate. In addition, the edible coatings showed a positive effect on maintaining higher concentration of total phenolics and total antioxidant activity, which decreased in control fruits associated with the over-ripening and senescence processes. Results from quality parameters and antioxidant activity suggested that the maximum storability period for control fruits was 8?days at 2?°C plus 2?days at 20?°C, while alginate-coated cherries could be stored with optimal quality and enhanced antioxidant activity up to 16?days at 2?°C plus 2?days at 20?°C.     

Effect of exogenous fludioxonil postharvest treatment on physiological response,physico-chemical,textural, phytochemical and sensory characteristics of pomegranate fruit

The study investigated the effects of fludioxonil (FLU) on the postharvest quality of pomegranate fruit (cv. Wonderful). Fruits were dipped in FLU concentrations (control, 150, 300 and 600 mg/L) and stored for 4 months at 5?°C and 90–95% relative humidity (RH) plus an additional 4 days at 20?°C and 65% RH. Effects of FLU were evaluated on physiological responses, quality and sensory attributes. Results showed that fruit weight loss and decay incidence were reduced by FLU treatment, with fruit treated with 600 mg/L concentration showing the best results. Fruit respiration rate was more influenced by storage duration than FLU concentration. The severity and occurrence of physiological disorders increased with storage duration but were more pronounced in fruits treated with FLU. Storage duration influenced fruit colour whereas aril colour was affected by FLU concentration. Untreated fruit showed better aril redness and chroma although treated fruit also had acceptable red colour. Chemical quality attributes of fruit juice were not significantly affected by FLU concentrations. Fruit treated with FLU had significantly (p?<?0.05) higher total phenolic content during storage although lower ascorbic acid content was observed compared to untreated fruit. Treating fruit with FLU resulted in better sensory attributes with regards to crispness, juiciness and sweetness. Overall, this study showed that fruit treated with FLU at 600 mg/L had the best quality with respect to decay incidence, weight loss, total phenolics and sensory attributes.     

Effect of high-voltage electrostatic field pretreatment on the antioxidant system in stored green mature tomatoes

BACKGROUND: High‐voltage electrostatic field (HVEF), as a feasible and non‐chemical technique, applied to food preservation is a new area of study. Our previous research suggested HVEF could maintain the quality of tomato in storage. The present article intensively investigated the effect of HVEF pretreatment on antioxidant system of green mature tomato in storage. RESULTS: Green mature tomatoes were exposed to negative (or positive) HVEF for 2 h at 20 °C and then stored for 24 days at 13 ± 1 °C, 85–90% relative humidity. The results indicated HVEF significantly reduced contents of O₂^? and H₂O₂ of tomato fruits during storage compared to the control. HVEF treatment also enhanced the activities of antioxidant enzymes including catalase, superoxide dismutase, ascorbate peroxidase and peroxidase. The contents of non‐enzyme antioxidant components including reduced glutathione, phenols and ascorbic acid also were increased by HVEF treatment. However, HVEF treatment did not increase the content of lycopene in tomato fruit. CONCLUSION: HVEF treatment could promote the antioxidant capacity of tomato fruits in storage. Further research is be highly recommended to understand the mechanisms improving the antioxidant capacity of tomato fruits by HVEF. Copyright © 2011 Society of Chemical Industry     

Effect of thermal treatment and storage on the stability of organic acids and the functional value of grapefruit juice

The effect of conventional and microwave pasteurisation on the main bioactive compounds of grapefruit juice and their stability during 2 months’ refrigerated and frozen storage was evaluated. Ascorbic acid (AA), vitamin C and organic acids were analysed by HPLC, whereas total phenols and antioxidant capacity (%DPPH) were measured by spectrophotometry. The results showed that conventional treatment led to a significant decrease in citric acid (from 1538 to 1478 mg/100 g) and AA (from 36 to 34.3 mg/100 g), whilst microwave pasteurisation preserved these compounds. Frozen storage maintained AA and vitamin C, especially in treated samples. Frozen non-treated samples and conventional pasteurised ones preserved about a 75% and 20% of the total phenols and antioxidant capacity, respectively, whilst in frozen microwave pasteurised juices this preservation was of 82% and 33%. From these results, the use of microwave energy may be proposed as an alternative to traditional heat pasteurisation in order to preserve the natural organoleptic characteristics and essential thermolabile nutrients of grapefruit juice.     

Alleviation of chilling injury in postharvest tomato fruit by preconditioning with ultraviolet irradiation

BACKGROUND: Tomato fruit is usually stored at low temperatures for delayed ripening and extended shelf life. However, tomato fruit is susceptible to chilling injury when exposed to low temperatures. In this study, the potential effects of preconditioning with UV‐C or UV‐B irradiation on chilling injury of postharvest tomato fruit were investigated. RESULTS: Mature–green tomato fruit were exposed to 4 kJ m^?2 UV‐C or 20 kJ m^?2 UV‐B irradiation and stored for 20 days at 2 °C and subsequently 10 days at 20 °C. UV irradiation was effective in reducing chilling injury index and delaying ethylene peak. Furthermore, UV irradiation preserved storage quality as manifested by reduced weight loss, better retention of firmness, and higher contents of total soluble solids, soluble protein and soluble sugar during subsequent storage at 20 °C. UV‐C irradiation significantly delayed the development of the red colour after 10 days of storage at 20 °C. On the other hand, UV irradiation decreased total phenolics content and antioxidant capacity, suggesting possibly reduced stress response to low temperature resulted from enhanced physiological adaptation by UV preconditioning. CONCLUSION: Our results suggest that preconditioning with UV‐C or UV‐B irradiation in appropriate doses had a positive effect on alleviating chilling injury in postharvest tomato fruit. Copyright © 2012 Society of Chemical Industry     

Effect of heat treatment and individual shrink packaging on quality and nutritional value of bell pepper stored at suboptimal temperature

The goal of this study was to develop a technology for prolonged storage of pepper fruit at low temperature, based on physical treatments and packaging materials. Physical and compositional changes of red bell pepper fruit (Capsicum annuum L. cv.’Selika’) were monitored during 21 days of cold storage (at 2 °C) plus 3 days at 20 °C (market simulation). Fruits were treated with tap and hot water and stored without packaging or sealing each fruit in individual shrink packaging (Cryovac®). This research revealed that individual shrink packaging following prestorage with hot water rinse (55 °C for 15 s) over brushes, significantly reduced weight loss, softening, decay incidence and chilling injury, while maintaining a quality. The wrapped fruit ripened normally (carotenoid content increased) during shelf‐life period, when shifted to 20 °C after unwrapping. This study showed that antioxidant levels of pepper fruit may be preserved during storage.     

Effect of delayed storage and continuous ethylene exposure on flesh reddening of ‘Royal Diamond’ plums

BACKGROUND: Flesh reddening has been described as one of the manifestations of plum fruits to low‐temperature storage for prolonged periods. The influence of factors such as ethylene and delayed storage has not been studied to date. In order to assess that, plum cv. ‘Royal Diamond’ fruits were (a) stored at 5 °C (control), (b) held at 20 °C for 2 days before storage at 5 °C (delayed storage) or (c) maintained at 5 °C under 15 µL L^?1 ethylene. Fruits were then transferred to 20 °C and ethylene, respiration, weight loss, firmness, soluble solids content, acidity, flesh reddening, anthocyanin accumulation and phenylalanine ammonia‐lyase (PAL) activity were determined. RESULTS: Delayed storage fruits showed more extensive flesh reddening than control fruits, with increased PAL activity and higher anthocyanin accumulation. Symptoms were expressed more markedly when fruits were stored at 5 °C in ethylene. CONCLUSION: Results indicated that the fruit ripening stage is a critical factor determining the susceptibility of ‘Royal Diamond’ plums to flesh reddening. Fruits continuously exposed to ethylene showed a dramatic increase in reddening, suggesting that ethylene contributes to the development of the disorder. Copyright © 2008 Society of Chemical Industry