Evaluation of postharvest storability of Ponkan mandarins stored at different temperatures

ABSTRACT The effects of storage temperature on postharvest storability, quality attributes and antioxidant enzyme activities of harvested Ponkan mandarins were investigated. Fresh fruits were randomly divided into four groups and stored at different temperatures [5 ± 1 °C (S5), 10 ± 1 °C (S10), 15 ± 1 °C (S15), and 20 ± 1 °C (S20 or control)] for 120 days. The results indicated that, compared with the control fruit, low-temperature storage at 10 °C significantly delayed the increase in fruit decay rate, weight loss, citrus colour index, respiration intensity, relative electrical conductivity, the accumulation of hydrogen peroxide and malondialdehyde, retarded the decline in L* value, retained high contents of total soluble solid, titratable acid, vitamin C, total phenol and total flavonoid, as well as higher activities of antioxidant enzymes – superoxide dismutase, catalase, peroxidase and ascorbic peroxidase. The principal component analysis results showed that low-temperature storage significantly maintained the postharvest quality of Ponkan mandarins, with fruit stored at 10 °C having no significant difference from the fruit stored at 5 °C, but markedly higher than those fruit stored at 15 °C. The comprehensive result of single-factor analysis and PCA showed that 10 °C could be used as the optimum storage temperature for improving the postharvest storability of Ponkan mandarins.

Effects of Edible Coating and Modified Atmosphere Technology on the Physiology and Quality of Mangoes after Low-Temperature Transportation at 13 °C in Vibration Mitigation Packaging

The mango is an important tropical fruit in the world, but it is easily perishable after harvest. In order to investigate the effect of the compound preservation technology on the physiology and quality of mangoes during transportation and storage, mangoes were treated with different packaging and preservation methods. All mangoes were subjected to simulated transportation by a vibration table for 24 h (180 r/min, 13 °C), and stored at 13 °C. The changes in the color, physicochemical characteristics, quality, and antioxidant-related enzymes of the mangoes were measured. The results show that the shelf life of inflatable bag packing (CK) was only 24 d, while the other treatments could be 30 d. The inflatable bag packing with modified atmosphere packaging (MAP) treatment (HPM) had the lowest yellowing degree (12.5%), disease index (34.4%), and mass loss (2.95%), at 30 d. Compared with the CK, the compound treatment containing MAP prolonged the peak respiration of the mangoes by 6 d and suppressed the increase in the total soluble solids and relative conductivity. Meanwhile, the HPM could effectively maintain moisture content, firmness, titratable acid, vitamin C, and the peroxidase and superoxide dismutase content, indicating that the treatment could maintain the better quality and antioxidation ability of mangoes. In summary, the MAP compound treatment better maintained the commercial characteristics of the mangoes, followed by the edible coating compound treatment. The results provide a theoretical reference for mango cushioning packaging and postharvest storage technology.

AGROBIOLOGICAL AND TECHNOLOGICAL STUDY OF PAMID GRAPEVINE VARIETY

An agrobiological and techno-logical study of the Pamid grape variety was carried out during the realization of different variants of loading with winter eyes during pruning. An agrobio-logical and technological study of the Pamid grape variety was carried out during the realiza-tion of different loading variants with winter eyes during pruning. It has been established that the phenophases of development during the vegetation period occur and take place al-most simultaneously in the same time periods, and the grapes ripen during the first ten days of September. With the increase in the number of knots of a vine and with their lengthening, there is a well-defined tendency of reducing the percentage of developed winter eyes, fruit-ing shoots, weight per 1 cluster, less of reduc-ing the fertility rate. The vines grow well under the pruning loads of the four variants and the grapes manage to ripen. The best combination of sugar and titratable acid content for wine production is in the grapes from the variants with a load of 6 and 7 knots of a vine. The number of knots has a proven strong or moder-ate negative effect on the percentage of devel-oped eyes, fruiting shoots, bunches, fertility rate, weight of one cluster and 100 grains, dur-ing both years of the study. The increase in the number of knots is in a moderate, positive cor-relation with the yield of one vine.

The Effects of Garlic and Red Chilli Pepper Powder on Physicochemical, Microbiological, and Sensory Properties of Cincalok

Cincalok, a traditional fermented shrimp, is prepared by mixing rebon shrimps (Acetes sp) with coarse salt and granulated sugar in a certain ratio. This research was aimed at studying the effect of adding garlic and red chilli pepper powder on the physicochemical, microbiological, and sensory properties of cincalok. Cincalok was made to be three recipes, namely, original cincalok, A, consists of 2 kg of rebon shrimp, 400 g of granulated sugar, and 100 g of coarse salt; B (A ingredients plus 20 g of red chilli pepper powder); and C (A ingredients plus 20 g of garlic powder). Sensory analysis was conducted on recipe A, and the colour was observed by the naked eye on days 0, 2, 4, 6, 8, 13, 18, 23, 28, 33, 43, 60, 90, 120, 150, and 180. According to the highest criterion score on sensory results, the panellists chose day 6 as the best fermentation for recipe A. The colour of recipe A started changing from pink to a light brown colour on the surface on day 28. Therefore, the physicochemical, microbiological, and sensory properties of each recipe were analyzed for 28 days. Overall, the water, ash, and fat content; titratable acid (TA); total volatile base nitrogen (TVBN); and amino acid nitrogen (AAN) showed insignificant differences ( p > 0.05 ) among the recipes during 28 days of the same observation. The crude protein, pH, and free fatty acid (FFA) of recipe C were significantly different ( p < 0.05 ) from recipes A and B. All recipes contained the total count of mesophilic anaerobic bacteria (TMABs) and the lactic acid bacteria (LABs) except Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, and Enterobacteriaceae for all observation times. The highest criterion score for consumer acceptability was awarded for recipe C followed by recipes B and A. The addition of garlic and red chilli pepper powder affected the physicochemical, microbiological, and sensory properties of cincalok.

Selenium Increases Fruit Quality By Reducing Ethylene Production And The Stone Cell Content In Pear (Pyrus Ussuriensis)

Background:Selenium (Se) is an essential trace element for both animals and plants. Se treatment can increase fruit Se concentration and shelf life. However, the mechanism underlying Se-delayed fruit ripening is still unclear.Results:In this research, two groups of Se (A and B treatments) were used to treat ‘Nanhong’ pear fruit. The results showed that these treatments could greatly increase the Se content but decreased the titratable acid content. Treatment A significantly decreased ethylene production, and the key genes controlling ethylene production, PuACSs and PuERF2, were inhibited by Se treatment. In addition, treatment A significantly decreased the stone cell content, and one lignin biosynthesis gene, PuC4H, was downregulated by treatment A.Concusions:Se treatment increased the Se content in pear fruit. In addition, Se decreased ethylene production and the stone cell content. Moreover, the key genes for ethylene production (PuACSs and PuERF2) and lignin biosynthesis (PuC4H) were also inhibited by Se treatment.

Effect of Aureobasidium Pullulans S-2 on the Postharvest Microbiome of Tomato During Storage

Background: Biological control of fruit postharvest diseases by antagonistic microorganisms has been considered an effective alternative to chemical fungicides. The influence of microbial antagonists on fruit-associated microbiome will provide a new perspective for in-depth study of the antagonistic mechanism. In this study, the biocontrol efficacy of A. pullulans S-2 against postharvest diseases of tomatoes was investigated. Meanwhile, the fungal and bacterial microbiota on tomato surfaces were examined by high-throughput sequencing. Results: A. pullulans S-2 can significantly inhibit the decay rate, maintain fruit firmness and reduce weight loss of tomatoes. In addition, the treatment group can maintain higher titratable acid, ascorbic acid and lycopene than the control group. After using A. pullulans S-2, more dramatic changes were observed in fungal diversity than bacterial in the microbiota. Aureobasidium was significantly enriched in the treatment group, while Cladosporium, Mycosphaerella, Alternaria and Penicillium were deficient compared with the control group. Pantoea, Brevibacterium, Brachybacterium, Serratia, Glutamicibacter and Pseudomonas also had significant differences between the two groups.Conclusions: This study demonstrated that the application of A. pullulans S-2 resulted in alterations in the bacterial and fungal community and that could inhibit pathogens and decrease fruit disease incidence. It provides new insights into the dynamics of the tomato's surface microbiome after microbial antagonist treatment.

Effects of sunlight exclusion on leaf gas exchange, berry composition, and wine flavour profile of Cabernet-Sauvignon from the foot of the north side of Mount Tianshan and a semi-arid continental climate

Canopy shading is a widely used viticultural strategy for mitigating early grape berry ripening caused by global warming. In this study, we covered half of the canopy with a black shade cloth from the pea-size stage to harvest. In the fruit zone, canopy shade treatment (ST) reduced daily average solar radiation by about 74.6 % compared to the untreated control (UC), and significantly reduced daily average temperature. ST leaves were found to have lower net assimilation rates and higher internal CO2 concentration than in UC, which resulted in reduced yield, bunch weight, cane starch and berry total soluble solids. A delayed development stage was found in ST berries which had lower pH and higher titratable acid than UC. ST increased both berry and wine anthocyanin concentration while significantly decreasing flavonol concentration. ST wines had higher concentrations of a number of ester compounds and β-damascenone than UC wines, thus significantly enhancing the floral and fruity aroma of ST wines. Higher C6/C9 and fatty acids concentrations in ST berries may have caused higher ester concentrations in ST wines. The results showed significant effects on metabolites in berries and wines caused by canopy shade.

Benzothiazole (BTH) Induced Resistance of Navel Orange Fruit and Maintained Fruit Quality during Storage

Current research aimed at studying the effect of benzothiazole (BTH) on the fruit quality and resistance against Penicillium italicum (P. italicum). Recently, a synthetically prepared novel BTH was introduced that elicits the induction of resistance against various diseases of fruits. However, little was reported on the effect of BTH on the disease resistance and fruit quality of postharvest navel orange fruit. In this study, 50 mg·L−1 BTH significantly reduced the decay rate of fruits during 36 days of storage at 20 ± 0.5°C ( P < 0.05 ). BTH markedly inhibited the weight loss rate in fruits ( P < 0.05 ) and effectively maintained higher soluble solid content (SSC), titratable acid (TA), and vitamin C (VC) content compared with control navel orange fruits. Further, BTH significantly suppressed the increase of disease incidence and lesion area of orange fruits challenged with P. italicum ( P < 0.05 ). BTH treatment significantly enhanced antioxidant capacity (DPPH, ABTS radical scavenging activity, and reducing power), and superoxide dismutase (SOD) and peroxidase (POD) activities were significantly increased, while the activity of catalase (CAT) was opposite to the former ( P < 0.05 ). The activities of β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), and chalcone isomerase (CHT) were significantly higher in BTH-treated navel orange fruits ( P < 0.05 ). Our results suggested that BTH treatment may be a promising treatment for maintaining the quality and inhibiting blue mold of postharvest navel orange in the future.

The Effect of Active Paper Packaging Enriched with Oleoresin from Solid Waste of Pressed Curcuma xanthorrhiza Roxb. Placement Methods on Quality of Refrigerated Strawberry (Fragaria x ananassa)

Strawberry is a popular and nutritious fruit. However, its improper post-harvest handling leads to quality degradation. The aim of this study was to investigate the effects of active paper packaging placements methods on strawberry (<em>Fragaria x ananassa</em>) quality during refrigerated storage. Strawberry quality was determined based on the physical (weight loss, hardness, color), chemical (pH, total titratable acid, total soluble solids and vitamin C content) and microbiological (total plate count) properties. The results of this study indicated that different placement methods of active paper packaging had no significant effect on the physical and chemical qualities; but it did affect the microbiological quality of the strawberries. At the end of the experiment (12 days), the microbial content of C (the bottom and walls), D (covering all surfaces) and E (cut into pieces) samples were significantly lower than the A (without active paper packaging) and B (the bottom) samples. The Total Plate Count (TPC) values of the control and B samples were higher than the maximum acceptable limit of 6 log10 colony-forming units (CFU) g^-1, while the other samples remained below the limit. These results indicated that a larger surface area of active paper that had contact with the strawberries provided better protection against microbes. Due to their microbial properties, C, D and E treatments maintained the strawberry quality for up to 12 days, compared with 9 days for control and B treatments. Active paper packaging containing oleoresin from solid waste of pressed <em>Curcuma xanthorrhiza</em> Roxb. can be applied to extend the shelf life of strawberries during refrigerated storage.