Effect of cassava starch coating on quality and shelf life of fresh-cut pineapple (Ananas comosus L. Merril cv "Pérola")

This research studied the influence of treatment with ascorbic acid, citric acid, and calcium lactate dipping and cassava starch edible coatings on quality parameters and shelf life of fresh-cut pineapple in slices during 12 d at 5 °C. After previous tests, the treatments selected for this study were samples dipped into antibrowning solution with 0.5% of ascorbic acid and 1% of citric acid, with and without 2% of calcium lactate and coated with 2% of cassava starch suspensions. Changes in weight loss, juice leakage, mechanical properties (stress at failure), color parameters (L* and H*), ascorbic acid content, sensory acceptance, and microbial growth of fruits were evaluated. Samples only treated with antibrowning agents were used as control. Edible coatings with and without calcium lactate were efficient in reducing weight loss, juice leakage, and maintaining firmness during storage. However, these samples showed more browning and the ascorbic acid content was reduced. All treatments presented good sensory acceptance (scores above 6). The determining factor of shelf life of pineapple slices was the microbial spoilage. A shelf life of 8 d was obtained for pineapple slices only treated with antibrowning agents. On the other hand, coated samples showed a reduced shelf life of 7 d and higher yeast and mold growth. Thus, although cassava starch coatings were efficient in reducing respiration rate, weight loss, and juice leakage and maintained mechanical properties, these treatments were not able to increase the shelf life of minimally processed pineapple. Practical Application: Pineapple fruit is highly appreciated for its aroma, flavor, and juiciness, but its immediate consumption is difficult. Therefore, pineapple is a potential fruit for minimal processing. However, shelf life of fresh-cut pineapple is very limited by changes in color, texture, appearance, off-flavors, and microbial growth. The use of edible coatings as gas and water vapor barrier and antibrowning agents can extend the storage time and maintain the quality of fresh-cut produce. Cassava starch and alginate coatings are alternative to preserve minimally processed pineapples without changing the quality parameters of fresh fruit. Thus, this study is useful for consumers and fresh-cut industry interested in knowing factors affecting shelf life and quality of fresh-cut pineapple.     

Proteome changes of fresh-cut Zizania latifolia during refrigerated (1?°C) storage

The total proteins from the fresh-cut Zizania latifolia during refrigerated storage were extracted and separated by two-dimensional electrophoresis (2-DE). A total of 657 protein spots were detected on the gels, among which 33 spots showed a significant change in protein abundance based on twofold difference. Using MALDI-TOF/TOF, 25 spots were identified, which were classified into five functional categories that included cell structure (32?%), stress response and defense (28?%), ripening and senescence (8?%), signal transduction (8?%), and unclear functional proteins (24?%). Of the 25 differentially expressed proteins, 10 were up-regulated and 15 were down-regulated. Among 10 up-regulated spots, 5 were related to cell structure, 2 to oxidative stress, 1 to ripening and senescence, 1 to signal transduction, and 1 to unclear functional proteins. For the 15 down-regulated spots, 5 were related to stress response, 3 to cell structure, 1 to ripening and senescence, 1 to signal transduction, and 5 to unclear functional proteins. These results indicate that specific proteins expressed in fresh-cut Z. latifolia during storage at 1?°C show a coordinated response to cope with wounding stress caused by fresh-cut processing.     

MRI ‘texture’ analysis of MR images of apples during ripening and storage

Images obtained by magnetic resonance imaging (MRI) of the apple varieties Idared, Redspur and Topaz during ripening and storage were analysed by texture analysis (TA) to determine the correlation between TA parameters and firmness, soluble solids content (SSC) and titratable acids. All varieties differ significantly in SSC, acidity and the firmness of fruits. Three sagital T2w slices measured at 4.7 T (resolution 256×256 pixels) were analysed numerically using the software MaZda 2.11 and the statistical package S-PLUS 4.5. A significant correlation was found between acidity and TA parameters such as sum average, sum variance and sum entropy. The dynamics of TA parameters during the periods of maturation and storage were described by polynomial functions.The following distinctive TA parameters were found: skewness and kurtosis (among histogram-based parameters), variance of absolute gradient (among gradient-based parameters), grey level nonuniformity (among run length matrix-based parameters) and especially some co-occurrence matrix-derived parameters such as correlation, sum average, sum variance and sum entropy (within 1-, 3-, and 5-pixel neighbourhoods). The TA parameter correlation obtained from MR images can be used for characterising fruit ripening.     

Effects of combined fumaric Acid-UV-C treatment and rapeseed protein-gelatin film packaging on the postharvest quality of ‘Seolhyang’ strawberries

‘Seolhyang’ strawberries were treated with fumaric acid (FA) and UV-C irradiation and packed with rapeseed protein-gelatin (RG) film containing 1% grapefruit seed extract (GSE). The initial population of total aerobic bacteria in the strawberries was 2.9 log CFU/g, while that of samples treated with FA plus UV-C and packed with RG film was 1.3 log CFU/g. For yeast and mold populations, the control had 2.6 log CFU/g, while samples treated with the combined treatment had 1.0 log CFU/g. These results suggest that combined postharvest treatment and RG film packaging can be useful for maintaining the quality of ‘Seolhyang’ strawberries.     

Influence of edible coating on quality of plum (<Emphasis Type="Italic">Prunus salicina</Emphasis> Lindl. cv. ‘Sapphire’)

Edible coating may enhance the boundary layer resistance resulting in enhanced shelf life of fruits. Plums (Prunus salicina Lindl. cv. ‘Sapphire’) were treated with coating material based on carbohydrate (Versasheen) with sorbitol as plasticizer and stored at 20 °C and 85% RH. The influence of coating on the gas transmission rates was estimated using a carrier of 100% cellulose paper. Coating treatment reduced the transmission rate of CO₂, O₂, and H₂O. Changes in fruit weight, fruit flesh firmness, color parameters (L*, a*, and hue angle), soluble solids content, pH, titratable acidity, ethylene, CO₂, malondialdehyde (MDA), and VIS/NIR fruit reflectance spectrum were recorded in 2-day interval. Edible coating was effective in delaying the increase of pH and the loss of firmness, titratable acidity, L*, hue angle, and MDA. The incorporation of sorbitol showed beneficial effects on decreasing the weight loss, CO₂, and ethylene exchange. In the room temperature storage period, not only fruit ripening was measurable in the VIS (350–750 nm) and NIR (750–1,400 nm) wavelength ranges due to the decrease in the fruit chlorophyll absorption but also water loss, respectively. After 5-day room temperature storage the chlorophyll absorption peak in the spectra was already beyond the detection limit in all treatments, while after 3-day storage, the coating effect on the spectral intensities was feasible to separate control from coated plums.     

Isolation and characterization culturable microbes on the surface of ‘Granny Smith’ apples treated with electrolyzed water during cold storage

Food Science and Biotechnology - Response of culturable microbes on the surface of apples treated with slightly alkaline electrolyzed water (SAIEW) is largely unexplored. Thus, the aim of this...     

Residual effect of atomised water vapour treatment on carbohydrate metabolism during ripening of cv “Fino de Jete” cherimoya fruit

Atomised hot water vapour at between 46 and 54 °C for 60 min was tested as a method of delaying ripening and extending shelf life in cv “Fino de Jete” cherimoya fruit (Annona cherimola Mill.). Heat treatment at 46 °C stimulated the respiration rate and starch degradation, induced ethylene production, increased the accumulation of soluble sugars and α-amylase activity, and moved the onset of ethylene production (OEP) forward. Treatment at 50 °C, and especially at 52 °C, delayed the climacteric peak and the OEP, decreased sugar and organic acid accumulation, and reduced α-amylase and invertase activity. The results obtained indicate that temperatures higher than 48 °C slowed physiological processes and carbohydrate metabolism and extend the shelf life of the cherimoya fruits, while temperatures higher than 52 °C blocked ripening irreversibly.     

Effect of 100 kPa O2 pretreatments time on physiology and quality of vacuum packed and coated fresh-cut apples

This research used different 100 kPa O₂ pretreatments time (0, 2, 4, and 6 hr) to investigate their effects on qualities of fresh-cut “Red Fuji” apples during cold storage. Fresh-cut apples were dipped in acid solution (composed of 1.53% ascorbic acid, 1.10% citric acid, and 0.51% CaCl₂) for 15 min and 5 g/L carboxymethylcellulose sodium edible coating (composed of 0.5% CMC, 0.01% Natamycin, and 0.015% Nisin) for 5 min. Then the slices were exposed to 100 kPa O₂ for different time before being vacuumed in polyethylene bags. The results showed that pretreatment with 100 kPa O₂ inhibited the surface browning, polyphenol oxidase and peroxidase activity and malondialdehyde. Moreover, 100 kPa O₂ pretreatment for 4 hr was more effective than other pretreatments time. Intact tissue structure and fewest molds and yeast count during 90 days of storage were also observed in pretreated for 4 hr samples during storage.     

Effect of α-tocopherol on the oxidative stability of horse oil-in-water emulsion during storage

Food Science and Biotechnology - Horse oil-in-water (O/W) emulsions were prepared and α-tocopherol was added at 0, 100, 200, and 500&nbsp;ppm (α-T0, α-T100, α-T200,...     

Influence of γ-irradiation on the reactive-oxygen metabolism of blueberry fruit during cold storage

To explore a safe, environmentally friendly, and efficient preservation technology for blueberry (Semen trigonellae), “Bluecrop” blueberry fruits were treated with different irradiation doses. During cold storage at 0 ± 5 °C, the decay rate, fruit firmness, and indices relating to respiration and reactive-oxygen metabolism were detected regularly. Results showed that irradiation treatment with 1.0 kGy to 2.5 kGy doses was able to inhibit the respiration intensity, ethylene production, and the improvement of lipoxygenase (LOX) activity, thus reducing the increase of malondialdehyde (MDA) content and the permeability of cell membranes. In addition, irradiation treatment can improve the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) to eliminate, on a continual basis, the constantly generated superoxide anions (O₂⁻) and hydrogen peroxide (H₂O₂), keeping them at a low level: ultimately, this effectively guaranteed the storage quality and postponed the senescence process in the blueberry fruits. Meanwhile, those irradiated at 2.5 kGy presented optimal preservation effects as the respiration was inhibited to the utmost extent and the anti-oxidisation effect was enhanced. The results prove that the ⁶⁰Co γ-irradiation treatment at proper doses is an effective method of storing post-harvest blueberry fruits at low temperatures.