Enhancement of Guava Nectar Characteristics by Reducing Heat Processing and Addition of Juniper (Juniperus communis) Extracts

Abstract

Guava is known to play a significant role in several diseases due to presence of numerous antioxidant polyphenols and flavonoids which damage during the postharvest and processing. The guava (Psidium guajava L.) nectar prepared by guava pulp supplemented with leaves or berries juniper (Juniperus communis L.) in water extracts (50 and 100 mg/L) were added in the final product then pasteurized and stored for 10 months at 4ºC. During storage, antioxidants contents (total polyphenols, total flavonoids, carotenoids, vitamin C, volatile oil, saponins and tannins), antioxidant activity, TSS and pH of guava nectar products were evaluated every 2 months till ten months storage. The sensory parameters of colour, flavour, taste and overall acceptability were also evaluated. It could be conclude that, the nectar containing juniper berries extract showed excessive antioxidant activity compared to guava nectar prepared at 70ºC/20 min without addition, also to other supplements after 10 months. In addition, it increased palatability of guava nectar for consumers. Moreover, the content of antioxidant at temperature of 70ºC for 20 min was observed to be stable and it enhanced sensory scores of the prepared nectar during storage as well as decreased energy costs.