Days Of Cold Storage Research Articles

Enhancement of storage life and quality maintenance of plum fruits

The present study was conducted to evaluate the effect of pre-harvest application of calcium chloride at 0.0, 1.0, 1.5, 2.0% concentrations on various physico-chemical parameters and enzymatic activities in plum fruits cv. Satluj Purple at various storage intervals (0, 7, 14, 21, 28 and 35 days) under low temperature conditions. Two sprays of CaCl2 @ 1.0% were most effective in maintaining the post-harvest quality attributes and efficiently reduced the physiological loss in weight (PLW), spoilage, pectin methyl esterase (PME) & cellulase activities and significantly delayed colour development & suppressed anthocyanin formation in plum fruits up to 28 days of cold storage. At the end of storage, two sprays of CaCl2 (1.0%) recorded higher fruit firmness (54%), sensory quality (24%), higher total soluble solids (5.70%), titratable acidity (41%), total sugars (7.14%) and total phenols (13%) as compared to control.

Efecto de diferentes temperaturas y tiempos de conservación sobre pupas de Apanteles gelechiidivoris (Hymenoptera: Braconidae)

Apanteles gelechiidivoris parasitoide de larvas de tercer estadio de Tuta absoluta, puede generar hasta 80 % de mortalidad de larvas en campo. Para producir masivamente el parasitoide es necesario tener almacenamiento en frío de pupas, para conservar cantidades importantes sin perder características biológicas. Se evaluaron diferentes temperaturas y tiempos de conservación en frío sobre parámetros biológicos en los estados de pupa y adulto. Las pupas se sometieron a 4, 8 y 12 °C por 7, 14, 21 y 28 días de almacenamiento. A 4 y 8 °C se retrasó el tiempo de emergencia después del almacenamiento frío, siendo más corto a siete días en cada temperatura. La emergencia de adultos fue más baja a 4 °C al disminuir significativamente conforme aumentaron los días de almacenamiento. En 8 y 12 °C se presentaron porcentajes de emergencia de 90 y 100, respectivamente, a los siete días de almacenamiento. No hubo efecto entre las temperaturas y días de almacenamiento, o su interacción, en la cantidad de hembras producidas (P > 0,05). La longevidad de adultos disminuyó al aumentar el tiempo de conservación. En 8 °C se presentó la mayor longevidad de adultos (9 días) a 7 y 14 días de almacenamiento. A 4 °C se afectó el parasitismo de las hembras que emergieron de pupas en los días de almacenamiento evaluados; en 8 °C, se obtuvo el porcentaje de parasitismo más alto (80 %) a 7 días de almacenamiento. Los resultados sugieren que las pupas pueden ser almacenadas hasta 14 días a 8 °C, sin afectar efectividad del parasitoide.

Cold Storage Influences Postharvest Chilling Injury and Quality of Peach Fruits

Peach (Prunus persica L.) fruits exhibit limited postharvest shelf and storage life due to rapid softening. Therefore, in the present study effect of cold storage was investigated on postharvest chilling injury (CI) and fruit quality during ripening following cold storage on five peach cultivars including ‘Peach Select No. 3’ (PS-3), ‘Florida Gold’ (FG) and ‘Florida King’ (FK) as early season maturing, and ‘Indian Blood’ (IB) and ‘Maria Delezia’ (MD) as late season maturing cultivars. Peach fruits harvested at commercial maturity were ripened at ambient conditions following cold storage for 0, 10 and 20 days at 0±1 °C with 80±5% RH. Data regarding peach fruit quality parameters and incidence of CI were recorded at fully ripe eating soft stage. Results indicated that apart from the cultivars, fruit weight loss, levels of soluble solid content (SSC) and sugars increased as the storage period was progressed. However, fruit firmness, titratable acidity (TA), and ascorbic acid content significantly reduced during cold storage. Among early season maturing peach cultivars, fruits of ‘FG’ and among late season maturing peach cultivars, fruits of ‘MD’ showed better postharvest shelf life and fruit quality during ripening following cold storage. The highest SSC and SSC: TA ratio were observed in ‘FG’ peach fruits; however, these fruits exhibited 50% and 75% CI after 10 and 20 days of cold storage, respectively. During first 10 days of cold storage, ‘PS-3’ peach fruits showed better taste with higher fruit firmness and ascorbic acid content, however, later on the highest level of CI was observed in these fruits. Among all the tested peach cultivars, the ‘IB’ peach fruits showed higher fruit firmness, lower weight loss, as well as acceptable biochemical fruit quality (SSC, SSC; TA, ascorbic acid content, total sugars) during 20 days of cold storage without showing any symptoms of CI.

Chitosan-Based Coating Enriched with Hairy Fig (Ficus hirta Vahl.) Fruit Extract for “Newhall” Navel Orange Preservation

A novel coating based on 1.5% chitosan (CH), enriched with or without hairy fig (Ficus hirta Vahl.) fruit extract (HFE), was applied to “Newhall” navel orange for improving the preservation effect. Changes in physicochemical indexes were analyzed over 120 days of cold storage. Uncoated fruit were used as the control. The CH-HFE coating, based on 1.5% CH enriched with HFE, exhibited the best preservation effect and showed the lowest decay rate (5.2%) and weight loss (5.16%). The CH-HFE coating could postpone the ripening and senescence of navel oranges, and maintain higher fruit quality by inhibiting respiration, decreasing the accumulation of malondialdehyde (MDA), and enhancing the activities of protective enzyme, including superoxide dismutase (SOD), peroxidase (POD), chitinase (CHI), and β-1,3-glucanase (GLU), which suggests that CH-HFE coating has the potential to improve the postharvest quality of “Newhall” navel orange and prolong the storage life.

Anti-diabetic Potency and Characteristics of Probiotic Goat-Milk Yogurt Supplemented with Roselle Extract during Cold Storage

This study aimed to evaluate the anti-diabetic potency by in vitro method and the characteristics of probiotic goat-milk yogurt supplemented with roselle extract during cold storage. The experiment used three treatments namely yogurt, probiotic yogurt, and probiotic yogurt supplemented with roselle extract. Yogurt was stored in cold storage (4 oC) and was evaluated for the characteristics and anti-diabetic potency on days 0, 5, 10, and 15. The anti-diabetic potency was analyzed by a-glucosidase inhibitory activity. The results showed that goat milk in this study had a good quality including fat, SNF, protein, lactose content, density, and freezing point. Roselle extract had anti-diabetic potency with 87.72% inhibition at 25% concentration and also had 13.64% IC50 value. The anti-diabetic potency was affected by the type of yogurt, storage duration, and their interaction (P<0.05). Viscosity and water activity were affected by storage duration (P<0.05), meanwhile titratable acidity and pH value were affected by the type of yogurt. Total lactic acid bacteria were affected by storage duration, and there was an interaction between the type of yogurt and storage duration. In conclusion, probiotic yogurt supplemented with roselle extract had the highest anti-diabetic potency among all treatments with 36.70% inhibition. The inhibitory activity of probiotic yogurt supplemented with roselle extract decreased during 15 days of cold storage. The inhibition was comparable with acarbose at 0.1-0.5 ppm concentration. Physical, chemical, and microbiological characteristics of yogurt in this study were good and could be consumed up to 15 days of cold storage.

Production of Novel Functional Yoghurt Fortified with Bovine Colostrum and Date Syrup for Children

The aim of this work was to study the effect of adding bovine colostrum and date syrup as natural ingredients on the nutritional value of yoghurt and it's quality during cold storage period. Functional yoghurt was prepared by using buffalo milk 3% fat, date syrup 5% for all treatments except the control and bovine colostrum was added at different ratios 5% (T2), 10% (T3) and 15% (T4). Then, all treatments were inoculated with 2% of yoghurt starter andstored at 5°C for 12 days. Samples of yoghurt were chemically, organoleptically, and microbiologically analyzed at 1st, 4th, 8th and 12th days of cold storage. It was observed that addition of date syrup and bovine colostrum for yoghurt were found to enhance significantly the content of total Solids (TS), total protein, immunoglobulin G (IgG), lactoferrin and minerals compared to the control. Also, most nutrients hade a slight increment during advanced storage period. The titratable acidity% of yoghurt samples slightly increased during storage periods, while the pH values decreased significantly.Yoghurt fortified with 10% (T3) and 15% (T4) of bovine colostrum had significantly higher viscosity values than that in the other treatments. Also, T4 had significantly lower syneresis than the other yoghurt treatments on 12th day of storage.No significant differences could be traced in flavour, appearance, body and texture and overall acceptability scores among all yoghurt treatments.The grams consumed of yoghurt to meet the daily requirement (GDR) for children aged 1-3 years of protein and (calcium, phosphorus, iron and zinc) significantly decreased by fortification of yoghurt with date syrup and bovine colostrum, while percent satisfaction (P.S.%/100g) of the daily needs in these nutrients significantly increased. In conclusion, fortification of yoghurt by adding date syrup and bovine colostrum enhanced nutritional value and quality of yoghurt.

Moringa extract enhances the fermentative, textural, and bioactive properties of yogurt

Yogurt is a fermented dairy food produced by lactic acid bacteria (LAB). Moringa oleifera is known for its bioactive properties. The aim of this study was to evaluate the effects of moringa on the fermentation, quality characteristics, and bioactive properties of yogurt. Yogurt was supplemented with 0–0.2% moringa extract (ME; hot water extract, 100 °C, 30 min) and fermented using mixed starter cultures (Streptococcus thermophilus, Lactobacillus acidophilus, and Bifidobacterium longum). Addition of ME to yogurt significantly accelerated the rate of fermentation by promoting growth of LAB. ME reduced syneresis up to 21% and enhanced the water-holding capacity by 17%. The viscosity of 0.2% ME yogurt was approximately 5-fold higher than control yogurt and radical-scavenging activity of ME yogurt increased up to 40% in a dose-dependent manner during the 21 days of cold storage. Sensory testing showed that the addition of 0.05% ME to yogurt did not negatively influence the overall acceptability of the product, compared to the control. The addition of ME to yogurt decreased the oxidative stress and increased the expression of antioxidant proteins in human colon cells. Thus, ME-fermented yogurt maintains the sensory acceptability and exerts positive health benefits because of increased LAB proliferation and enhanced antioxidant properties.

Improving postharvest quality and antioxidant capacity of sweet cherry fruit by storage at near-freezing temperature

To improve postharvest quality of sweet cherry, the effect of near-freezing temperature (NFT) storage was evaluated by analyses of postharvest characteristics, biological compounds and antioxidant property. The fruit were stored at 5 °C, 0 °C and NFT (determined by biological freezing curve) respectively. NFT extended the longest storage period (up to 100 d) and maintained the consumable and better sensory quality. NFT storage delayed the senescence by suppressing respiration rate, softening, malondiadehyde accumulation and decay rate. Compared to 0 °C storage, the decay rate of fruit stored at NFT was approximately 4∼8-fold lower at the end of storage and shelf-life. NFT also reduced weight loss and biological disorder (such as pitting and pedicel browing) during sweet cherry storage. Moreover, NFT delayed color changes and improved the levels of soluble solids content (SSC), titratable acidity, ascorbic acid, total phenolic compounds, total flavnoids and total anthocyanins in sweet cherry. The SSC in fruit at NFT was about 1.2–1.4 fold higher than that of 0 °C in both cultivars sweet cherry during shelf life after 80 days of cold storage. Additionally, NFT storage also enhanced antioxidant property and delayed the peak value of antioxidant capacity in fruit. These results suggested that NFT storage could be considered as a preservation method for improving postharvest quality and antioxidant property of sweet cherry fruit.

Assessment the viability properties of Lactobacillus casei strain using labneh as a carrier

Our study was conducted in two stages; the first stage was to examine the fructose fermentation profile by Lactobacillus (Lb.) casei FEGY9973. The second stage was to investigate the viability properties of Lb. casei either during cold storage of labneh or under simulated gastrointestinal tract (GIT) conditions. Labneh as a carrier medium was classified into four treatments; the first one con- tained 2% free cells of Lb. casei as a control. The second, third and fourth treatments used 2% of encapsulated cells of Lb. casei with different capsule materials, including alginate-milk, sodium alginate and &kappa;-carrageenan served as T1, T2 and T3 respectively. The physiochemical, microbiological and sensory properties of labneh during 15 days of cold storage were shown. Moreover, the viability of free and encapsulated Lb. casei sub- jected to some manufacturing and simulated GIT conditions was tested. It was revealed that lactate was the major metabolite in the medium for colonic fermentation, where- as no amounts of ethanol could be detected. Moreover, labneh samples including free cells of Lb. casei had lower pH values than treatments containing microcapsules of Lb. casei. The levels of moisture, acetaldehyde and diacetyle in treatments with different encapsulated materials were increased during the cold storage period. Accordingly, labneh samples with encapsulated Lb. casei had higher sensory scores than the control. In addition, labneh samples with Lb. casei in milk-alginate microcapsules showed a high viability during cold storage and under simulated GIT conditions. A significant decrease in the viability of free or encapsulated Lb. casei was observed at 15 days of cold storage. Encapsulated Lb. casei by alginate-milk was more resistant during the cold storage period and under simulated gastric conditions than the other two treatments.

EFFECT OF PREHARVEST APPLICATIONS OF CALCIUM, ANTI- ETHYLENE COMPOUNDS AND THEIR COMBINATIONS ON “CANINO” APRICOT FRUIT QUALITY AND STORABILITY

This study was conducted during two sequential seasons of 2015 and 2016 in a private orchard located in El-Khattaba District, Menoufia Governorate, Egypt to investigate the influence of calcium chloride (CaCl2) at 2%, anti-ethylene compounds namely Aminoethoxyvinylglycine (AVG) at 150 ppm and 1- Methylcyclopropene (1-MCP) at 25 ppm in addition to their combinations (CaCl2 plus AVG, CaCl2 plus 1- MCP, AVG plus 1-MCP and finally CaCl2 plus AVG and 1-MCP, at the same concentrations) on fruit drop at harvest and yield as well as firmness, jelly pulp and other quality parameters of “Canino” apricot fruits during cold storage at 0oC and 90- 95% RH for one month. During 2015 and 2016 seasons, apricot trees were sprayed three times starting after full bloom, fruit setting and finally ten days before harvest. Quality of sprayed fruits was evaluated at harvest and every ten days of cold storage. The results showed that external browning, internal browning, jelly pulp, fresh weight loss, total sugars, total soluble solids (TSS), TSS to acidity ratio, carotene content were increased, while firmness, electrolyte leakage, vitamin C, acidity, chlorophylls a and b contents were decreased with the progress of cold storage duration. Furthermore, the results revealed that all used treatments reduced external and internal browning symptoms in addition to jelly pulp formation and fruit fresh weight loss. Moreover, the treatments lessened electrolyte leakage of fruits, retarded the loss of fruit firmness and were effective on keeping the physical and chemical qualities relative to the control treatment. Finally, this study indicated that the addition of CaCl2 to anti- ethylene compounds was more effective than the individual application of each compound on reducing fruit abscission, increasing average fruit weight and yield/tree at harvest plus retarding the loss of firmness, other physical and chemical qualities and prolonging the storability of “Canino” apricots stored at 0oC, especially the combination of AVG and 1-MCP in the presence of CaCl2.

Developing functional yogurt rich in bioactive peptides and gamma-aminobutyric acid related to cardiovascular health

This study aimed to develop a novel functional yogurt through improves the production of bioactive components that have biological functions. Yogurts were manufactured from skim milk fortified with whey protein concentrate (WPC) and were fermented with high viscosity yogurt starter as a single or mixed with highly proteolytic co-culture. In one treatment, trypsin was used to partially hydrolysis of milk before fermentation with mixed starter. Yogurts were investigated for viscosity, water-holding capacity (WHC), sensory attributes, proteolytic activity, γ-aminobutyric acid (GABA) content and biological activities. The fortification with WPC increased the viscosity and WHC, while addition of trypsin decreased the values of these properties. High proteolytic and biological activities were observed by addition of WPC and mixed starter whereas treatment with trypsin had greater effects. Yogurt treated with mixed starter and trypsin had the high content of GABA. Sensorial, all yogurt treatments were acceptable and the yogurt treated with highly proteolytic co-culture gained the highest score. The biological activities and GABA content of all yogurts increased after 14 days of cold storage. It is concluded that highly proteolytic starter and partial proteolysis could be used to produce functional yogurt enriched in bioactive peptides and GABA with cardiovascular health benefits for consumers.

Effect of ozone or carbon dioxide pre-treatment during long-term storage of organic table grapes with modified atmosphere packaging

The aim of this study was to maintain the quality of organic table grapes extending its shelf-life during long-term storage by using organic approved methods. The effectiveness of pre-treatments with different concentrations of O3 (5, 10, 20 μL L−1) or CO2 (50%, 70%) followed by storage under modified atmosphere packaging (2%O25%CO2) were evaluated on late-season organic Scarlotta table grapes as alternatives to the usual commercial SO2 application. The main quality attributes as mass loss, decay incidence, rachis chlorophyll content, antioxidant activity, phenolic compounds and acetaldehyde content, were measured at harvest and after 15, 30, 45 days of cold storage (0 °C) under simulated shipping conditions and one week of shelf-life (15 °C). The O3 at 20 μL L−1 controlled the concentration of acetaldehyde, preserved rachis chlorophyll content and skin colour; in addition, the cumulative decay incidence was reduced compared to untreated samples, however, CO2 caused organoleptic quality loss with strong stem browning and perceived off-flavours; moreover, it was effective to preserve the initial sensory quality and to control the decay. The results encourage the use of this alternative approach treatment in other cultivars and under commercial conditions.

The quality of Gold Queen Hami melons stored under different temperatures

Abstract Low temperature storage prolongs the postharvest life of various fresh fruits and vegetables. However, the actual storage temperature may also significantly influence fruit and vegetable quality. In the present study, we stored Gold Queen Hami melons at three different temperatures [21 °C (control), 3 °C, and 0.5 °C (0 ± 0.5 °C)] for 36 days. The humidity for all three temperatures conditions was between 75% and 85%. The results indicated a correlation between chilling injury in Gold Queen Hami melons and storage temperature and time. Different degrees of chilling injury in Gold Queen Hami melons were observed after storage at 3 °C and 0.5 °C, whereas these were detected later when stored at 3 °C. In addition, the rotting rate, weight loss rate, and chilling injury index at 3 °C were significantly lower compared to that at 0.5 °C storage temperature. Compared to other temperatures, storage at 3 °C was associated with a delay in fruit rotting, sustained high fatty acid desaturase and adenosine triphosphatase (ATPase) activity, a decrease in lipoxygenase activity, enhanced cold resistance, and extended total storage period. At 21 °C, no chilling injury was observed, although extensive weight loss and high rotting rates were detected. Moreover, two highly expressed genes, namely, JhMYB24 and JhMYB48, were screened and selected from the Gold Queen Hami melon transcriptome database. Real-time PCR analysis showed that the expression of JhMYB24 and JhMYB48 continuously increased under cold stress and peaked at the 18th day of cold storage. The expression of JhMYB24 and JhMYB48 at 3 °C was significantly higher than that at 0.5 °C or 21 °C. Together, our results demonstrate that regulating enzyme activity and upregulating the expression of JhMYB24 and JhMYB48 alleviate cold stress in fruits stored at 3 °C, thereby maintaining high fruit quality.

Influence of Biologically Inert Protective Coating Based on Pectin Substances on PUFA Quality and Shelf-Life of Frozen Fish

The influence of a biologically inert protective coating on the basis of low-esterified pectin substances (LEPS) on the qualitative indicators of frozen fish and its lipids is studied in this paper: organoleptic, physico-chemical, structural-mechanical and biochemical changes in fish of various methods of freezing during 240 days of cold storage. The limiting periods of storage of a silver carp (Hypophthalmichthys molitrix) of different ways of freezing are established. The prolongation of the shelf life of refrigeration and the higher quality indices of frozen fish with the use of a protective coating based on low-esterified pectin substances is due to the reduction of shrinkage and inhibition of hydrolytic decomposition and oxidative damage of lipids by preventing the contact of the surface of frozen fish with oxygen in the air. In addition, when freezing fish in a calcium chloride solution, the LEPS-based coatings exhibit barrier properties, preventing the diffusion of calcium ions into the muscle tissue of the product. Such a mechanism of influence on the duration of fish storage of various methods of freezing during prolonged cold storage allows to obtain frozen fish with high quality indices and to substantially reduce losses during refrigerated storage.

Nanoemulsion based alginate organic coating for shelf life extension of okra

Abstract Okra holds major share of domestic and export vegetable market, but has a short shelf life owing to desiccation and fungal spoilage. Alginate coating containing nanoemulsified basil (Ocimum basilicum. L) oil was attempted for maintaining its postharvest quality and preventing spoilage. O/W nanoemulsion was prepared by using basil oil with synthetic surfactant and a naturally sourced surfactant: Tween 20 and aqueous extract of Sapindus mukorossi using ultrasonication respectively. Alginate coatings with basil oil nano-emulsified with Tween 20 (ATNE) and Sapindus extract (ASNE) were compared for their effect on PLW (Physiological loss in weight), colour, texture and acceptability of okra pods stored at 5 ± 1 °C and 24 ± 2 °C. Coatings were able to retard loss of moisture, colour and firmness during storage. Compared to 10.05% weight loss in uncoated pods (control), PLW in ASNE and ATNE was recorded as 7.38% and 8.32% respectively after 4 days of cold storage. Increase in L* value during storage was 26.39% for control pods compared to 14.98% in coated pods. a* value and browning index revealed better effectiveness of ASNE coating for colour retention during storage. Developed formulations were found effective against spoilage fungi Penicillium chrysogenum and Aspergillus flavus. Effective concentration for 50% inhibition of pathogens was determined using probit analysis. EC50 values were lower for sapindus emulsified basil oil over Tween 20 based nano-emulsion. In vivo trials on okra inoculated with Penicillium chrysogenum and Aspergillus flavus yielded promising results. Thus alginate coating with basil oil nano-emulsified with Sapindus extract can emerge as a promising non-chemical approach towards extending postharvest quality and shelf life of okra.

An embedded system based on DSP platform and PCA-SVM algorithms for rapid beef meat freshness prediction and identification

Statistical and artificial intelligence learning algorithms such as Principal Component Analysis (PCA) and Support Vector Machine (SVM) are widely used in many meat quality assessment applications to classify and predict the freshness of beef meat. This paper presents the implementation of the PCA and SVM algorithms on an embedded system based on a Digital Signal Processor (DSP). A dataset of eighty-one hue, saturation, and intensity (HSI) beef meat images was used. The PCA is used as a projection and prediction model where the SVM is used for the classification and identification of the beef meat. Results obtained from PCA projection model on a desktop system using Matlab software show the projection of three groups which represent the degree of beef meat freshness during the days of cold storage. A perfect prediction of the new unknown samples was obtained by PCA prediction model. A successful rate 100% of classification and identification was obtained by SVM. The PCA and SVM methods were implemented on the C6678 multi-core DSP. The implementation results of these algorithms were similar as those obtained by Matlab software. The processing time of the algorithms measured on the embedded system was lower compared to the desktop system. The embedded platforms based on DSP as portable tools can be used to predict or identify the sample beef meat freshness anywhere and in real-time.

Effect of lyophilization on food grade liposomes loaded with conjugated linoleic acid

The effect of lyophilization and rehydration medium on a liposome system for conjugated linoleic acid (CLA) delivery was studied. Liposomes were prepared by ethanol injection method employing soy phosphatidylcholine and CLA isomers 9c, 11t and 10t, 12c. Two rehydration media were assessed: a food simulant (distilled water) and the original medium used for liposome preparation (ethanol: water 1:9). Rehydrated liposomes were characterized in size, morphology, CLA encapsulation efficiency and membrane fluidity, at 3 and 30 days of cold storage. CLA loaded liposomes presented better stability and lower size than control liposomes without CLA through storage time, regardless of the rehydration medium. These facts could be related with spin label EPR measurements: CLA disordered the outer part of the lipid bilayer increasing fluidity, and ordered the inner part of the bilayer decreasing fluidity, which indicates a more packed membrane in the hydrophobic region. In all cases Transmission Electronic Microscopy images showed nanometric sized and oligo-lamellar vesicles. Liposomes preserved CLA isomers with high encapsulation efficiency: no differences were noticed between fresh and lyophilized samples. No influence of rehydration medium was noticed for the majority of the studied parameters. We have successfully developed efficient liposomal systems for bioactive compounds delivery in food applications.

Postharvest longevity of 'BRS Vitória' seedless grapes subjected to cold storage and acibenzolar-S-methyl application

Abstract: The objective of this work was to evaluate cold storage periods and postharvest longevity of the seedless table grape 'BRS Vitória' subjected to the application of the disease-resistance inducer acibenzolar-S-methyl (ASM). Bunches were treated or not with 1% ASM, placed individually in plastic clamshell trays and stored in a cold chamber at 2±1ºC, at a high relative humidity, for three periods (30, 45, and 60 days), followed by a 5-day period of shelf life in plastic clamshells, at 22±2ºC. After each storage period, gray mold (Botrytis cinerea) incidence was evaluated, and the physicochemical analysis was performed. A completely randomized design, with four replicates, was used in two 2x3 factorial arrangements: one evaluating ASM application and cold storage periods; and another, ASM and cold storage + shelf-life periods. ASM did not change the physicochemical characteristics of the bunches, and the incidence of gray mold was lower than 1% in all treatments. Water loss from bunches increased with storage periods. Even without ASM application, 'BRS Vitória' grape can preserve its postharvest quality for up to 60 days of cold storage, plus five days of shelf life in plastic clamshells.

Debranching of pea starch using pullulanase and ultrasonication synergistically to enhance slowly digestible and resistant starch

Pullulanase (P) and ultrasonication (U) were simultaneously applied to debranch pea starch to enhance slowly digestible starch (SDS) and resistant starch (RS) fractions in the debranched pea starch (DPS). A synergistic debranching effect was found under conditions of pullulanase (40 npun/g) and ultrasonication (100% amplitude in pulse mode, 1 min on followed by 9 min off), which produced 73.5% linear glucans, 18% SDS and 26% RS in the resulting DPS-PU after 6 h of debranching. Even when autoclaving the DPS-PU at 118 °C for 30 min, following cooldown, 11% SDS and 25% RS were retained in the DPS-PU, compared with 0% SDS and 12% RS in autoclaved native pea starch. The SDS fraction in autoclaved DPS-PU further increased to 16% while the RS content remained constant during 14 days of cold storage. In summary, DPS-PU is high in linear glucans, low in starch digestibility and has a thermally stable RS fraction.

Relationship between flesh browning and the activities of polyphenol oxidase, peroxidase and phenylalanine ammonia-lyase in feijoa fruit

Flesh browning is the main postharvest disorder limiting the storage life of feijoa fruit produced in southern Brazil. The aim of this study was to evaluate the relationship between the activity of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) and incidence of flesh browning in five Brazilian genotypes of feijoa: cultivars 'Alcântara', 'Helena', 'Mattos' and 'Nonante', and the access 2316. Fruit of all genotypes were harvested at commercial maturity in 2013, and cold stored for 7 and 14 days (4±1°C/90±5% RH), followed by 48 h of shelf life (23±1°C/75±5% RH). The activities of PPO, POD and PAL and incidence of fresh browning were assessed at the harvest and after 7 and 14 days of cold storage (followed by shelf life). On average of all genotypes, the activity of PPO increased 29% from harvest to 7 days of cold storage, and 37% from 7 to 14 days of cold storage. PPO activity after 14 days of cold storage was highest in 'Mattos' and lowest in 'Helena'. POD activity was low in all genotypes and decreased from harvest until 14 days of cold storage. In all genotypes, PAL activity did not change from harvest until 7 days of cold storage but increased from 7 to 14 days of cold storage (by 11-28%) in 'Alcântara', 'Helena' and 'access 2316'. 'Mattos' had the highest PAL activity, which did not change from harvest until 14 days of cold storage. The severity of pulp browning after 14 days of cold storage (followed by shelf life) was higher in 'Mattos', 'Alcântara' and 'access 2316', and lower in 'Nonante' and 'Helena'. The results show that the occurrence of flesh browning in the fruit of feijoa genotypes cultivated in southern Brazil is associated fruit senescence, and related to the increase of PPO and PAL activities during storage (especially of PPO). POD activity was low in all genotypes of feijoa and, therefore, the enzyme seems to have little effect on the internal browning.