Shelf life (days)
Effect of packaging and storage treatments on shelf life of minimally processed jackfruit portion have been shown in Fig 1.
Fig 1: Effect of packaging and storage on shelf life of jack fruit portions.
There was significant difference among the seven treatments in shelf life of both mature firm fleshed and soft fleshed portions stored under refrigeration and under ambient conditions. The vacuum packed firm fleshed and soft fleshed portions under refrigeration showed the highest shelf life of 20.33 days and 15.33 days, respectively. In both types, vacuum packaged portions had highest shelf life as compared to remaining treatment combinations. Vacuum packaging removes substantial amount of oxygen from the packaging system and reduction in ambient air from the package helps in reduction of deterioration progress (Wiley, 2009)
. Vacuum packaging of respiring foods is clearly a form of modified atmospheric packaging; by removal of the air, biological action continues to alter or modify the atmosphere inside the package. As a general rule, when the oxygen concentration was decreased, the respiration rate and the storage life were extended. This was followed by portions under Modified Atmospheric Packaging in laminated pouches with silica gel with a shelf life of 18.33 days which was on par with shrink wrapped portions with shelf life of 18.00 days. In soft fleshed type also, portions under MAP with silica gel had 12.33 days shelf life. Least shelf life (2.33 and 1.66 days) was recorded by unwrapped firm and soft fleshed portions under refrigeration. Under ambient conditions, the vacuum packed firm fleshed and soft fleshed portions had the highest shelf life of only 3.00 and 2.00 days, respectively. Under ambient conditions, all unwrapped firm fleshed portions had the least shelf life (0.33 days) and soft fleshed portions were spoilt within a day (0.00 days shelf life).
Physiological loss in weight (%)
Effect of packaging on physiological loss in weight (PLW) of minimally processed jackfruit portions stored under refrigeration is shown in Fig 2a and 2b.
Fig 2: Effect of packaging on PLW of mature jack fruit portions under refrigeration.
The data revealed that the physiological loss in weight increased during storage period for all the portions indicating deterioration at the end of shelf life. Mean physiological loss in weight was least (1.08%) for the firm fleshed portions under vacuum packaging followed by portions packed under MAP with silica gel (1.59%) after 20 days of storage (Fig 2a.). The results of the present study were similar in soft fleshed portions also, where the mean PLW after 15 days was least (1.10%) for portions under vacuum packaging (Fig 2b.) which was followed by portions packed under MAP with silica gel (1.30%) sachet. Highest mean weight loss (16.97 and 15.00%) was recorded by the unwrapped firm and soft fleshed portions. respectively under refrigerated storage. Chemical additives with various modified atmosphere packaging techniques at low temperature conditions was beneficial in reducing decay, maintaining quality and extending the shelf-life of minimally processed jackfruit bulbs (Saxena et al., 2008).
Jackfruit portions are also a type of minimally processed products and portions in vacuum had least PLW which is a direct measure of shelf life and quality.
The minimally processed portioned jackfruits under ambient storage were spoilt within 2 days. Under ambient condition mean PLW was least for both fruit types (0.21 for firm fleshed and 0.43% for soft fleshed) after 2 days of storage under vacuum packaging (Fig 3).
Fig 3: Effect of packaging on PLW of portions under ambient storage.
The effect of packaging on marketability of jackfruit portions is shown in Fig 4 and b.
Fig 4: Effect of packaging on marketability of jack fruit portions under refrigeration.
As the ambient storage portions spoilt within three days, marketability could be made only for portions under refrigeration. Both types of jack fruit portions showed reduction in marketability during storage. The vacuum packed firm fleshed portions had high mean marketability of 94.54% after 20 days of storage and soft fleshed had highest marketability of 88.75% after 15 days of storage. Unwrapped firm fleshed portions lost marketability within six days of storage with mean marketability of 13.63% (Fig 4a) and unwrapped soft fleshed portions had lowest marketability of 15.41% (Fig 4b.) Packaging had a significant effect on physiological weight loss, decay percentage, color score, overall acceptability and marketability, as reported by Haile1(2018)
As the ambient stored minimally processed jackfruit portions were spoilt within three days of storage and hence organoleptic analysis could be made only for refrigerated portions.
Effect of packaging and storage on colour score of minimally processed jackfruit portions is shown in Table 1 and 2.
Table 1: Effect of packaging on sensory score of minimally processed varikka portions under refrigeration.
Color score of both types decreased during storage irrespective of packaging materials. Mean color score of firm fleshed was maximum (7.5) for portions packed under vacuum packaging at 20th
day of storage followed by portions packed under MAP with silica gel (6.7). Unwrapped jackfruit portions had least (3.1) mean color score on 2nd
day of storage (Table 1). Vacuum packed mature soft fleshed portions had maximum (7.1) mean score for colour on 15th day of storage and least (3.2) color score was recorded by the unwrapped jackfruit portions on 2nd day of storage.
Table 2: Effect of packaging on sensory score of minimally processed koozha portions under refrigeration.
Effect of packaging and storage conditions on organoleptic score for texture of minimally processed jackfruit portions, as judged by sensory scoring is shown in Table 1 and 2. Texture scores of all jack fruit types decreased during storage irrespective of packaging materials. Maximum (7.9) mean score for texture was for portioned firm fleshed under vacuum packaging followed by portions under MAP with silica gel (6.1) after 20 days of storage. Least textural score (2.9) was recorded by unwrapped portioned jackfruit (Table 1) on 2nd
day of storage. Maximum mean score for texture (6.9) was for soft fleshed portions under vacuum packaging on 15th
day of storage and least (3.1) mean score for texture was for unwrapped portioned jackfruit after 2nd
day of storage (Table 2).
Effect of packaging and storage on taste of jackfruit portions, as judged by sensory scoring is shown in Tables 1 and 2. The highest (7.5) mean score for taste was for firm fleshed portions under vacuum packaging followed by sample packed under MAP with silica gel (6.7) on 20th
day of storage. Unwrapped jackfruit had least mean score (3.1) for taste on 2nd day (Table 1). Maximum (6.8) mean score for taste was recorded by the soft fleshed portions under vacuum packaging on 15 days after storage, whereas least (2.9) mean score for taste was recorded by the unwrapped jackfruit portions after 2nd
day of storage (Table 2).
In general, packaging and storage treatments influenced all physiological parameters such as shelf life, PLW and marketabilty of all jack fruit types significantly. Vacuum packed portions stored under refrigeration showed the highest shelf life, least physiological loss in weight (PLW), high marketability and maximum mean rank value for colour, texture and taste in both types of jackfruit portions evaluated. The product under the present study was a type of fresh cut produce or a minimally processed product with high metabolic activity compared to intact whole jackfruit. Gorny et al., (2000)
reported the capability of MAP in lengthening shelf life of several fresh cut horticultural products. Vacuum packaging, a type of modification of atmosphere condition with in the package prolongs the freshness of the product due to reduced concentration of air around the product. Vacuum packaging, refrigeration and use of laminated pouches had helped in protecting the jack portions from deterioration by extending shelf life with high marketability and overall acceptability.
Silica gel is an approved desiccant or moisture scrubber used in fruit and vegetable packaging, which was kept in the form of moisture absorbing sachet. According to Chauhan et al., (2006)
application of moisture scrubber enhanced the shelf life of banana up to 18 days. As a result of respiration of the product, water vapour accumulates inside the package and depending on the product nature; this may bring about undesirable changes such as absorption of surface moisture, generation of liquid water and condensation on the packaging material. The resulting effect on the appearance of the product may lead to rejection by the consumer. As the product under the present experiment is a highly respiring fresh cut commodity, accumulation of liquid water and condensation was high inside the package, which was absorbed by the silica gel, kept inside the package. Desiccants protect sensitive products against water and humidity (Brody et al., 2001)
. Offered in clay, molecular sieve and silica gel forms, they absorb moisture that enters or remains in a package. There was no desiccation of the product as evidenced by reduced PLW.
The portions kept under shrink wrap packaging were also equal to MAP with silica gel. Shrink wrap film maintains high humidity levels reducing water loss from packaged produce and the potential for mould and bacterial growth and spoilage is reduced by the anti- fogging treatment, thus enhancing shelf life of the commodity (John, 2010)
. The results of present findings are in accordance with reports of Nanda et al., (2000)
and Dhall et al., (2012)
who had observed enhanced shelf life of pomegranate and cucumbers, respectively under shrink wrapping.
Cling film used in the present experiment was a LDPE film of 15 micron thickness and wrapping the produce with a low gauge PE film could not give any protection to the product. Though they have low water vapour transmission rate, their gas permeability is high, resulting in permeation of gases through the package film and ultimate damage of the commodity (John, 2010)
. As the film formed intimate package with the produce, jackfruit portions was fresh looking initially.
Modified atmospheric packaging (MAP) with KMnO4 could not maintain the quality characters of jackfruit portions. Ethylene, a plant hormone produced during the ripening of fruits and vegetables is responsible for modifying their quality and longevity by increasing respiration rates, softening tissues and accelerating ageing. KMnO4
, an ethylene scavenger was used along with the packaging material after enclosing in a sachet. KMnO4
oxidizes ethylene to acetate and ethanol, changing colour from purple to brown. Even though the direct contact between KMnO4
and jack fruit portion was avoided by carefully stapling the KMnO4
sachets with the package, condensation of highly respiring jackfruit portions resulted in spreading of colour inside the package affecting appearance of the commodity and reducing acceptability.
Unwrapped fruit portions lost marketability within 6 days of storage and none of the packaging systems was better in maintaining the physiological quality parameters. Unpacked fruit portions resulted in high moisture loss by being in direct contact with outer environment. This clearly indicates the influence of packaging in reducing the physiological weight loss and moisture loss of fruits, thus diminishing the loss of quality and acceptability during distribution and marketing. Even under packaging the product undergoes metabolic activities and resulting deteriorative changes. Similar trend was observed in refrigerated and ambient storage conditions in case of minimally processed jackfruit portions as reported by Survase et al., (2021)
in red pumpkin, where pre-treated with xanthan gum @ 0.50% i.e
packed in 200 gauge polyethylene bag with 2% vents and stored at refrigerator storage (5±1°C) recorded the minimum physiological loss in weight with maximum retention of physico-chemical composition at the end of 12th
day of storage. Ambient storage was not at all efficient in maintaining physiological quality parameters as evidenced by low shelf life, low marketability and high PLW. Refrigeration could retain the produce quality and low temperature storage (4°C) has been reported to extend the shelf life of MP commodities (Piga et al., 2000).
Compared to other packaging systems, vacuum packaging was comparatively better even under ambient storage too.
Based on effectiveness of packaging materials and storage conditions in maintaining physiological, organoletic quality and marketability, portions under vacuum packaging in laminated pouches of at PP/LDPE under refrigeration was found to be the best treatment for enhancing the shelf life of minimally processed jackfruit portions.