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Abstract.
Muntingia calabura is an underexploited fruit in South of Vietnam. Muntingia calabura L is a fast growing medicinal plant, attracts fruit eating birds such as flower peckers. It is a sweet fruit and mainly used as fresh fruit consumption. Muntingia calabura fruit is rich in antioxidant polyphenol and possess significant antioxidant activity, is an important and interesting finding. Straw berry leaves (Muntingia calabura) contain antioxidants that generally form by phenolic or pholifenols, the sinamat acid derivatives, flavonoids, tocopherols, coumarin and polifungsional acids. Flavonoids that have an antioxidant activity consist of flavonol, flavanon, flavones, isoflavones, catechins and kalkon. There is limited study mentioning to processing of this phytochemical leaf. Therefore we explored a herbal tea production from this leaf by focusing on the effect of different parameters such as the effect of blanching temperature and time; heat pump drying temperature and storage condition to vitamin C (mg/100g), flavonoid (mg/g) and sensory score of the dried Muntingia calabura leaf tea. Results showed that Muntingia calabura leaves should be blanched in hot water 95°C at 5 seconds in the present of CaCl2 0.5% and then beeing dried by heat pump dryer at 40°C until 8% moisture. The final herbal tea could be preserved under vacuum in PET/AL/PE bag at 4°C to maintain flavonoid content for 12 months.
Keywords: Muntingia calabura, blanching, drying, heat pump, herbal tea, vacuum
1. Introduction
Drying is the most common method of medicinal plant preservation and, due to high investment and energy costs, drying is also a large expense in medicinal plant production. Drug quality and consequently earnings are significantly influenced by the drying regime. Heat sensitive properties (aromatic, medicinal, culinary, colour) provide specialty crops with their high market value. Care must be taken when drying specialty crops not to cause extreme losses of heat sensitive properties. Therefore, they must be dried at low temperatures for longer periods of time resulting in large power requirements for dryer operation. Heat pumps can simultaneously raise the temperature from that of the waste heat stream and multiply the energy supplied to the heat pump. Pereira et al. (2004) justified the addition of a heat pump system to a convention re-circulating convection dryer. They found that heat pumps are able to deliver more energy than...