Influence of physicochemical parameters on storage stability: Microbiological quality of fresh unpasteurized fruit juices

Abstract

Fresh juices rich in health and nutritional benefits are valued for their fresh flavor, taste, and aroma. These juices' quality however is affected by factors like temperature, light, and microbiological contamination significantly changing physicochemical parameters and storage stability. Physicochemical and microbiological analyses of passion fruit, pineapple, and mango juices in dark and light bottles at 24°C and 4°C were conducted in Kampala, Uganda for 12 days. Physicochemical parameters significantly reduced (p < .05) storage stability of fresh juices, while no significant changes (p > .05) were observed for the microbiological analyses. pH values ranged from 3.0 to 4.2 (dark) bottles and 2.9 to 4.0 (light) bottles for juices at 24°C and 4°C. °Brix values were from 1.0 to 5.5 for dark and clear bottles at 24°C and 4°C. TTA (%) values ranged from 1.1 to 7.2 (dark) bottles and 1.1 to 7.4 for (light) bottles at 24°C and 4°C. Ascorbic acid content ranged from 3.5 to 61.0 mg/ 100 ml and 5.5 to 56.7 mg/100 ml for juices in dark and clear bottles, respectively. total plate counts ranged from 1.3 × 10___ to 3.3 × 107 CFU/ml (dark bottles at 24°C) to 3.5 × 10³ to 3.3 × 108 CFU/ml (dark bottles at 4°C). For juices in light bottles, total plate counts ranged from 1.8 × 10___ to 8.0 × 107 CFU/ml (24°C) and 2.7 × 10___ to 1.5 × 108 CFU/ml (4°C). High microbial loads suggest the use of poor processing techniques and lack of good hygiene which lower quality and reduce storage stability of juices. Storage temperature greatly reduces physicochemical parameters both at ambient and refrigeration temperatures. This implies that temperature control for unpasteurized juices is critical in order to inhibit microorganism metabolic activities which accelerate biodeterioration leading to spoilage and short shelf life. Fresh unpasteurized juices stored at 24°C and 4°C may safely be consumed within 1 and 2 days, respectively.

Combined application of organic and inorganic fertilizers influenced biochemical qualities of fruit juice from yellow passion fruit (Passiflora edulis Deg.) genotypes

“…Dias et al (2011) reported increased vitamin C content of passion fruit juice with the application of bovine bio-fertilizer. On the other hand, °Brix values (9.82 to 9.30) in this study were higher than the values (1.0 to 3.0) recorded by Kaddumukasa (2017) but lower than the value of 12.0 documented by Codex Alimentarius (2005).…”

Determination of Some Quality and Safety Parameters for Black Raisin Juice

“…Furthermore, there were no significant difference in the population of microorganisms in all fresh samples compares the samples at the middle and the end of storage period in refrigerator or the survival of microorganisms in fresh raisin juice was slightly increased after one and two weeks of storage in refrigerator and these results are in accordance with a previous study done by Elsheikh et al (2014) that investigated the total viable count was nil at zero time of storage and started to increase after 2 months. On teh other hand, this results agrees with results obtained by Kaddumukasa (2017) in the microbiological analyses of passion fruit, pineapple, and mango juices in dark and light bottles at 24°C and 4°C were conducted in Kampala, Uganda for 12 days for juices.…”

Is overnight fresh juice drinkable? The shelf life prediction of non-industrial fresh watermelon juice based on the nutritional quality, microbial safety quality, and sensory quality

“…Fresh juice not only provides rich nutrients, a pleasurable taste, and an attractive color, but it also has no additives and is pure, natural, and minimally processed. Therefore, in recent years, the consumption of fresh juice has significantly trended upward, and fresh juice is gaining much popularity among customers throughout the world; it has gradually become the new favorite of the beverage industry (2,3). Non-industrial fresh watermelon juice (FWJ) is one of the most common fresh juices in the market; it is an excellent product to quench thirst and relieve the heat in summer and the tropics.…”

“…For example, a juice shop prepares fresh juice in advance and waits for customers to buy it within a period of time; a housewife prepares too much juice to drink at a single time and drinks the remainder the next day; and a juice shop prepares too much juice to sell in 1 day and then stores the remainder to be sold the next day (6). In addition, compared with industrialized juice, non-industrial fresh juice, including non-industrial FWJ, is usually drank directly after juicing without any sterilization treatment, which results in the problem that bacteria are easily bred and cause microbial contamination during storage and retail (2,(7)(8)(9). In addition, as non-industrial FWJ does not contain any food additives, its sensory index and nutritional and functional indicators will change significantly with the extension of storage time; it is easy to cause sensory deterioration and nutritional loss if stored improperly or for a longer storage time (2,10).…”