Search

Grape juice, non-fermented products, which is prepared from the concentration of grape juice and has a high nutritional and medicinal value due to having a suitable amount of fast-digesting, monosaccharides, minerals, vitamins, organic acids and phenolic compounds, flavonoids. The type and percentage of its constituent compounds are affected by genotype and environmental conditions, as well as the conditions of production and concentration of grape juice also affects its quality characteristics. In this study, grape juice from two varieties of red Gazane and green Fakhri grape using different concentration methods including heating in atmospheric conditions and microwave, as well as, different concentrations of syrup soil (0.5 and 1%) with carbonate Calcium production and then the amounts of phenolic compounds, flavonoids, anthocyanins and antioxidant properties as well as physicochemical parameters (pH, acidity, total sugar and brix) and sensory were studied. The results of the present study showed that the highest phenolic, flavonoid, anthocyanin and free radical scavenging activity of DPPH was observed in red grape treatments and microwave heating method (p <0.05). Red grapes had higher pH, acidity, brix and total sugar values than green grapes and the use of microwave heating method had a positive effect on these characteristics compared to atmospheric heating method. The composition of syrup soil (1%) and calcium carbonate increased pH and decreased brix and acidity (p <0.05). Physicochemical properties of all produced syrup were within the permissible limits of the Iranian national standard. The highest sensory score was also observed in red grape+ microwave + syrup soil 0.5% and red grape+ microwave + syrup soil 1% + calcium carbonate Therefore, it seems that the produced grape syrup, while having suitable physicochemical properties, can be considered as a source of bioactive compounds with high antioxidant activity in food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The public is increasingly concerned about the safety of fruit, so the production and preservation of high-quality fresh fruit is becoming more and more important. This work evaluated the use of a 405 nm light emitting diode (LED) for postharvest preservation of fresh green grapes under tropical temperatures of 29 ± 1 °C. LED exposure to green grapes was done for various lengths of time (0, 24, and 48 hours), corresponding to different dosages of 0, 0.7, and 1.4 kJ/cm2. After 7 days of testing, the results found that 95%, 75%, and 5% of the grapes had been invaded by microorganisms, which matched the pretreatment with LED light at 0 h, 24h, and 48 h. According to the first-order kinetic model, the constant rate of weight loss (k) was 0.039 ± 0.005 (control, LED-0h), 0.037 ± 0.009 (LED-24h), 0.062 ± 0.005 (day−1) (LED-48h), with all p-value < 0.001. Compared to the control condition, weight loss was mostly unaffected by LED-24h. No appreciable color changes were seen for LED-24h and 48h, indicating that the fruit has retained its original color as well as its freshness. In control samples, however, one-third of L* and a* values were reduced from baseline. The control samples are susceptible to fungus infection like Guignardia bidwellii, however, color development and morphology showed that LED-48h with an irradiation dose of 1.4 kJ/cm2 had outstanding anti-fungal effectiveness. These LEDs are a possible replacement for fluorescent lights in fruit market showcase and storage rooms, serving as both a source of illumination and protection against microbial contamination.