Effect of postharvest hydrogen sulphide on lignification and biochemical markers of pointed gourd.

Hydrogen sulphide (H2 S) has emerged as a gasotransmitter molecule that modulates several physiological functions in plants, specially, different biotic and abiotic stresses. Pointed gourd (PG) fruits start losing their soft texture and appealing colour within 2-3 days of harvest, resulting in poor marketability and shelf life. Here, the effect of exogenous H2 S (1 and 2 mm) application on lignification and other biochemical markers linked to ripening, shelf-life and edible quality of PG was assessed during cold (12 °C, 85-90% RH) and ambient (27 ± 2 °C, 55 ± 5% RH) storage. The synergistic effect of H2 S was recorded during simulated storage at ambient conditions. Postharvest H2 S treatment (1 mm) effectively delayed yellowing and chlorophyll loss (four-fold reduction) and maintained the phenolic content and higher antioxidant activity (36%). The H2 S-treated PG fruits had significantly lower lignification and membrane permeability i.e. 15% and 13%, respectively, than control samples. H2 S-treated fruit also maintained higher PAL and lower PPO activity. Therefore, postharvest application of H2 S (2 mm) could be effective in maintaining postharvest quality of PG fruits and extending the marketing period.

Hydrogen sulphide infiltration downregulates oxidative metabolism and extends postharvest life of banana.

Hydrogen sulphide (H2 S) has emerged as a potential regulator of plant defence against different abiotic stresses. As a climacteric fruit, banana undergoes oxidative stresses shortly after harvest, resulting in faster ripening and senescence. This work examines the effects of vacuum infiltrated H2 S on ripening inhibition of banana. Banana fruits were vacuum infiltrated with 1 mm H2 S. Effects on oxidative stress markers, physiological changes, bioactive compounds and antioxidant potentials were examined during storage at 25 °C and 75-80% RH. Results indicate that treated fruits were less affected by oxidative stress, as evident by lower accumulation of ROS (superoxide and peroxide ions), elevated phenols content and antioxidant capacity. The ripening inhibitory effects of H2 S delayed chlorophyll loss and reduced ethylene and CO2 production. H2 S infiltration also reduced MDA accumulation and electrolytic leakage, resulting in longer shelf life. Vacuum infiltration with H2 S had a protective effect on postharvest banana through overcoming the deleterious effect of ROS and strengthening antioxidant potential. Thus, this method could be promising for enhanced preservation of banana during storage.

Promising applications of cold plasma for microbial safety, chemical decontamination and quality enhancement in fruits.

Consumers' demand is increasing for safe foods without impairing the phytochemical and sensory quality. In turn, it has increased research interest in the exploration of innovative food processing technologies. Cold plasma technology is getting popularity now days owing to its high efficacy in decontamination of microbes in fruit and fruit-based products. As a on-thermal approach, plasma processing maintains the quality of fruits and minimizes the thermal effects on nutritional properties. Cold plasma is also exploited for inactivating enzymes and degrading pesticides as both are directly related with quality loss and presently are most important concerns in fresh produce industry. The present review covers the influence of cold plasma technology on reducing microbial risks and enhancing the quality attributes in fruits.

Oregano Essential Oil as an Antimicrobial and Antioxidant Additive in Food Products.

Food consumers and industries urged the need of natural alternatives to assure food safety and quality. As a response, the use of natural compounds from herbs and spices is an alternative to synthetic additives associated with toxic problems. This review discusses the antimicrobial and antioxidant activity of oregano essential oil (OEO) and its potential as a food additive. Oregano is a plant that has been used as a food seasoning since ancient times. The common name of oregano is given to several species: Origanum (family: Lamiaceae) and Lippia (family: Verbenaceae), amongst others. The main compounds identified in the different OEOs are carvacrol and thymol, which are responsible for the characteristic odor, antimicrobial, and antioxidant activity; however, their content may vary according to the species, harvesting season, and geographical sources. These substances as antibacterial agents make the cell membrane permeable due to its impregnation in the hydrophobic domains, this effect is higher against gram positive bacteria. In addition, the OEO has antioxidant properties effective in retarding the process of lipid peroxidation in fatty foods, and scavenging free radicals. In this perspective, the present review analyzes and discusses the state of the art about the actual and potential uses of OEO as an antimicrobial and antioxidant food additives.