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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.

This study examined the quality characteristics of jelly prepared with green grape juice (GJ). The pH, oBrix value, color, texture, and sensory evaluation of the jelly were measured. The pH of the jelly significantly decreased with increasing amount of GJ over the range of 3.25-5.27. The oBrix value of the jelly showed a significantly higher result as the amount of GJ increased (p<0.001). Lightness (L) and redness (a) decreased with increasing amount of GJ, and yellowness (b) increased. In the texture measurement, the GJ-100 sample group with a high substitute rate of GJ showed high hardness, gumminess, and chewiness (p<0.001). The results of principal component analysis (PCA) showed that the sample groups with high GJ content were classified as having relatively strong yellowness, sweet aroma, metallic aroma, grassy aroma, sweetness, sourness, green grape skin taste, and astringency. In the acceptance test, the GJ-50 sample group was evaluated to be high in flavor (p<0.001) and overall acceptance (p<0.01). However, sample groups consisting of 50% or more GJ were evaluated to be significantly strong in terms of astringency. Therefore, further study needs to be conducted about improving astringency in the future. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnONPs) were synthesized by green protocol using Mimusops elengi fruit extract as a novel natural resource. The synthesized particles were polyhedral (mostly hexagonal) in shape between 14 - 48 nm with an average size of 24.75 ± 0.78 nm. Nano zinc oxide (ZnO) at concentrations of 2% (w/w) and 4% (w/w), were incorporated into agar matrix. Solution casting method was used to fabricate the bionanocomposite films with ZnONPs in agar. Surface morphology, particle size, crystallinity, thermal stability and functional groups were determined using SEM, TEM, XRD, TGA and FTIR, respectively. Loading of ZnONPs in composite films improved thermal stability, elongation and film thickness, whereas tensile strength and transparency decreased. The films were used for packaging of green grapes, and appearance of the fruit was observed during ambient storage. Grapes packaged in composite films showed fresh appearance up to 14 and 21 days in ambient conditions for 2% (w/w) and 4% (w/w) ZnONPs in films, respectively. The results showed the potential of the fabricated agar-ZnO nanocomposite film as a promising packaging material to enhance postharvest shelf-life of fresh fruits like green grapes.