engleski

Improving storage potential of fresh goji berry (Lycium barbarum L.) fruits using postharvest hot water dip treatments

Goji berries are considered as the latest super food or fruit due to its excellent nutritive and medicinal properties and usually consumed and marketed as a dried or as a juice due to its short storage life and lack of information about its postharvest behavior. The current study was comprised of two sections ; in first part different storage temperatures (-2, 0, 10 and 20°C) were tested to evaluate the optimum storage temperature for seedling derived goji berries for 12 days of storage as part of preliminary studies. In second part, different hot water treatments (48, 50 and 52°C) with three exposure durations (2, 4 and 6 min) for two storage time durations (8 and 16 days) to improve the storage potential and post-storage fruit quality of goji berries. The fruits stored at 0 °C and -2 °C appeared with lowest weight losses (13.08 and 14.95%) and significantly different from fruit stored at 10 °C (18.29%) for 12 days of storage. Whereas, the fruits stored at 20°C deteriorated within a day due to fungal decay. However, some storage disorders like cracking, peel disorder, shriveling were observed in the fruits stored under -2 and 10 °C. There were significant differences in the phytochemical attributes like SSC, TA, SSC/TA ratio, total polyphenols, DPPH and ABTS while CIE color variables were found non-significant. In addition, the fruits stored under 0 °C appeared fresh and healthy and hence received highest scores during sensory analysis and strongly recommended for storage of this important horticultural commodity. A marked reduction in total weight loss and decaying percentages were recorded using HWD 50°C 2m and 50°C 4m throughout the observations recorded from 2 days’ interval till 16 days of storage. The storage time days appeared significantly different and influential factors in determining weight loss percentages in goji berries. The total weight losses recorded with 50°C 2m after 8 days (2.96%) and 16 days (7.14%) were significantly lowest than control samples after 8 (3.42%) and 48°C 4m after 16 days of storage (9.13%). Similarly, the total decaying percentages recorded with 50°C 2m after 8 days (2.88%) and 16 days (8.75%) were significantly lowest than control samples after 8 (8.08%) and 50°C 6m (16.33%) and control samples (15.65%) after 16 days of storage. Slight increase and decrease in all CIE color variables recorded in all treatments throughout the storage period. However, most of the color indexes like a/b CI, CCI, COL, CIRG1 increased and CIRG2 slightly decreased from harvest initial observations till 16 days of storage. There were significant different levels recorded in all sources of variances in terms of SSC, TA and SSC/TA ratio. The SSC and TA as malic acid values significantly increased from harvest initial till 16 days of storage. Whereas, slightly decreased in the SSC/Ta ratio in all treated goji berries recorded. The total polyphenols increased from harvest initial (196.90 mg GAE·100 g-1 Fw) to 16 days (244.85 mg GAE·100 g-1 Fw) of storage in HWD 50°C 4m. The highest DPPH antioxidant activity values were obtained in fruits treated with HWD 50°C 6m (326.42 µmol TE·100 g-1 Fw) after 8 days of storage and with HWD 50°C 4m (344.827 µmol TE·100 g-1 Fw) after 16 days of storage. The highest (1080.60 and 1197.90 µmol TE·100 g-1 Fw) ABTS antioxidant activity levels were recorded in goji fruits treated with higher level of HWD 52°C 4m for both 8 and 16 days of storage. Whereas, the chlorophyll contents significantly increased from harvest initial (46.86 µg·g-1 Fw) to 16 days of storage in some treatments like HWDs 48°C 4m (57.01 µg·g-1 Fw) and 50°C 2m (78.77 57.01 µg·g-1 Fw) and control samples (65.62 µg·g-1 Fw). While, some HWDs treatments showed a declined trend as well. The sensory attributes were favorable and prominent in the goji fruits treated with HWDs 50°C 2m and HWD 50°C 4m during both storage time durations. However, there were significant reduction in scores recorded in the fruits after 16 days of storage in all of the treatments. The lack of this important information was the main limiting factor and inspiration for testing lecithin as a postharvest treatment to improve the storage potential of goji berries that might help in developing its market potential as fresh fruit. The findings obtained ensures the highest fruit quality of goji berries in terms of all biochemical and phytochemical characteristics, color and sensory attributes with significantly reduced weight loss and decaying percentages during 8 and 16 days of storage may help further for goji berries possible marketing and availability as fresh fruits worldwide.

Goji berries, hot water dip treatments, Lycium barbarum L., postharvest, storage

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