Putrescine with Aloe vera gel coating improves bioactive compounds and quality of table grape under cold storage

Aromatic Profiling of New Table Grape Varieties Using Gas Chromatography/Mass Spectrometry and Olfactometry

The aim of this study is the aromatic characterization of new table grape varieties, namely Guzun (V. vinifera), Melona (V. vinifera), Cotton Candy (V. vinifera), IVC SA3 (V. labrusca), and IVC SB1 (V. labrusca). The qualitative and quantitative analysis of odorant molecules present in the berries allows for the definition of the aroma profile of the grape. This analysis benefits from the progress of analytical techniques and sensory methodologies. Gas chromatography/mass detection enable the efficient detection of the substances present and their concentrations. Through the coupling of gas chromatography with sensory detection (gas chromatography-olfactometry), it is possible to correlate the compounds detected by gas chromatography with olfactory stimuli, exploiting the human olfactory system. Aroma, a significant flavor component, is an important attribute of table grape that contributes to defining their quality. This characteristic is highly valued by consumers, and consequently, the market asks for table grapes with a particular or new aroma. Aromatic characterization is a crucial step in the study of the table grape varieties to evaluate their potential at the commercial level or, for instance, in breeding programs focusing on organoleptic properties.

Physicochemical and quality characters of fresh pistachio (Pistacia vera L.) cultivars in response to chitosan/ZnO nanocomposite coating

This study was done to evaluate the effect of pre-harvest foliar application with chitosan (500 and 1000 mg L-1), Nano-chitosan (250 and 500 mg L-1), and chitosan/ZnO nanocomposite (250 and 500 mg L-1) coatings on the quality and shelf life of fresh pistachios of "Akbari" and "Ahmad Aghaei" cultivars during storage. The results showed that 250 and 500 mg L-1 of chitosan/ZnO coatings significantly affected the shelf life of pistachios up to 35 and 40 days, respectively; in addition, chitosan/ZnO nanocomposite in both cultivars reduced weight loss, aflatoxin contamination, decay, polyphenol oxidase and glutathione-peroxidase enzymes, peroxide value, free fatty acids, and improve firmness, sensory properties, protein, oil content, carbohydrate, antioxidant properties, anthocyanin, phenol, and flavonoid. These results indicated that using chitosan/ZnO (250 and 500 mg L-1) is a promising efficient, safe, and environmentally friendly method for preserving the quality of fresh pistachios. It reduces hull browning and minimizes post-harvest losses.

Quality evaluation of fresh pistachios (Pistacia vera L.) cultivars coated with chitosan/TiO2 nanocomposite

Fresh pistachios are rich in dietary fiber, minerals and unsaturated fatty acids, but they have a short shelf life. This investigation examined the effect of pre-harvest foliar application with chitosan (500 and 1000 mg. L-1), nano-chitosan (250 and 500 mg. L-1), and chitosan/TiO2 nanocomposite (250 and 500 mg. L-1) coating films on the postharvest physiology and storage of fresh pistachios (Pistacia vera cvs. Akbari and Ahmad Aghaei) cultivar during storage at 4 ± 0.5 °C. It was found that, fresh pistachios' shelf life could by increased by up to 30 days by the use of chitosan/TiO2 nanocomposite coating for foliar application. The decay index of the composite coated fruits was 4-6 % lower than that of the control group, and after 50-60 days the bacterial contamination appeared in cultivars; respectively. The nanocomposite treatments reduced the fruits weight between 30 and 40 %, which was 15 % higher that of than uncoated fruits. The pre-harvest application of chitosan/TiO2 coating reduced microbial contamination, weight loss, phenylalanine ammonialyase (PAL) activity and saturated fatty acids, and increased unsaturated fatty acids, antioxidant properties, sensory properties, essential minerals, superoxide dismutase (SOD), quality indicators and shelf life. These results demonstrated that the chitosan/TiO2 (250 and 500 mg. L-1) coating film effectively preserved the nutrient composition, sensory quality, nutritional value, antioxidant capacity and shelf life of fresh pistachio.