バジル精油添加アロエベラゲルコーティングによる農産物の品質保持効果

概要

The total cost of product due to in ju ry and spoil at the t ime of marketing is higher than during the production phase. Thus, it is necessary to find a new strategy to delay senescence after harvesting, during storage and distribution of products to achieve reasonable shelf life. In recent years, consumers attention has increased to natural food with beneficial effect on health rather than foods combined with chemical additives. Natural edible coatings as a safe and eco-friendly preservative are now receiving significant attention to e xtend the shelf life and delay deterio rate of diffe rent kind of fru its and vegetables. Aloe vera gel is a typ ica l e xa mple of postharvest edible coating with high maintenance of postharvest qualities applied on various types of fru its. Aloe vera gel as a natural edible coating has been recently developed in food productions and pharmaceutical industries due to antimicrobial activity, biochemical and biodegradability properties such as anticancer, antioxidant, anti-allerg ic , anti-inflammatory, immunomodulatory, hepatoprotective and antidiabetic. These properties of Aloe vera arise from rich content of polysaccharides combined with soluble sugars, proteins, vitamins, and minerals, albeit with relatively low lip id content (0.07% – 0.42%). Howeve r, lip id content plays a key ro le in hydrophobic barrier properties of the edible coating. It is reported that coatings contained both polysaccharide and lip id form more effective barrier to moisture loss and gas permeability compared to polysaccharide-based alone. Among possible sources, the essential oil of basil (Ocimum basilicum L.) plant with 0.64 g/ 100 g fatty acid could be a good selection which uses in food industry as antimicrobial and antioxidant additive agents in food products. Bas il plant of Lamiaceae family can grow in various regions with different climates around the world and contain in protein, fatty acid, vita mins, and min era ls. Thus, to maximize coating treatment efficiency, a combination of Aloe vera gel as polysaccharide and basil oil as lipid has been proposed.

　In th is research, the effect of Aloe vera gel alone and enriched with basil oil at 500 and 1000 µL L-1 concentration as a new coating on three crops including peach as climacteric fru it, strawberries as non-climacteric fruit and button mushroom with spongy texture were investigated.

　Applying Aloe vera gel mixed with basil oil at 1000 µL L-1 concentration on peaches indicated the highest firmness, lowest weight loss and total soluble solid in compare other treatments.

　Application of Aloe vera gel with 1000 µL L-1 concentration of basil oil on stra wberry at 4 ◦C storage, showed retarded the weight loss, softening, respiration rate and fungal mycelium growth on medium during cold storage and had beneficial effects on maintaining total acidity, flavor quality and color of the fru it. Finally, the sensory analysis confirmed that the visual acceptance of the coated fru it was more than the uncoated samples.

　Aloe vera gel containing 1000 µL L-1 concentration of basil oil reduced weight loss and respiration on strawberry at ambient temperature (20 ◦C) more than other t reatments and prevented surface color change. This treatment showed beneficial inhibition on the in vitro and in vivo study of fungal in fection at ambient temperature. Furthermore, sensory evaluation obtained the scores for coated sample strawberries higher than uncoated.

　Aloe vera gel and bas il oil at both concentrations on button mushroom in cold storage decelerated respiration rate and weight loss and preserved firmness by inhibition of relative electric leakage and malondialdehyde accumulation. Furthermore, browning index were delayed through in flation of phenolic contents, antioxidant and phenylalanine ammonia lyase activities and reduction of polyphenol oxidase activity. In addition, sensory evaluation presented the high score for mushrooms t reated with Aloe vera gel plus basil oil at 1000 µL L-1 concentration treatment.

　The combination of Aloe vera gel and bas il oil as an incorporation of polysaccharide and lip id leads to the formation of higher barrier efficacy and delayed senescence process of these different types of crops. Finally, it is recommended to use Aloe vera gel supplemented with basil o il especially at of 1000 µL L-1 concentration as a potential candidate for senescence inhibition of stored peach, strawberry and mushroom.