González Cristina M, Gil Rebeca, Moraga Gemma, Salvador Alejandra
Departamento de Tecnología de Alimentos, Universitat Politècnica de Valencia, Camí de Vera s/n, 46021 Valencia, Spain.
Centro de Tecnología Postcosecha, Instituto Valenciano de Investigaciones Agrarias, CRTA, Moncada-Náquera km 4.5, Moncada, 46113 Valencia, Spain.
Foods. 2021 Mar 18;10(3):647. doi: 10.3390/foods10030647.
Persimmon ( L.f.) crop has markedly increased in Spain, and "Rojo Brillante" persimmon is the main cultivated variety. This astringent cultivar requires de-astringency treatment before commercialization, which may involve an extra cost. Its short commercial season implies handling large volumes of fruits with consequent postharvest losses. Therefore, the development of derived added-value products is of much interest. In this study, astringent and non-astringent "Rojo Brillante" persimmons were dehydrated by following a natural drying method used in Asia. The drying kinetics and physico-chemical properties were analyzed for 81 days. The results indicated subsequent reductions in weight, water content, and water activity throughout the drying process, and the equatorial diameter decreased. All the employed thin-layer mathematical models were suitable for representing the drying characteristics of both products with similar behavior. The effective water diffusivity values were 5.07 × 10 m s and 6.07 × 10 m s for astringent and non-astringent persimmon samples, respectively. The drying treatment significantly decreased the soluble tannins content, and the astringent samples obtained similar values to those obtained for the non-astringent samples in 20 days. The external and internal flesh of the astringent fruit remained orange through the drying period, while brown coloration in the non-astringent fruit was observed after 57 drying days. Therefore, prior de-astringency treatment would not be necessary.
在西班牙，柿子（柿属）的产量显著增加，“Rojo Brillante”柿子是主要的栽培品种。这种涩柿品种在商业化之前需要进行脱涩处理，这可能会带来额外成本。其较短的商业季意味着要处理大量果实，从而导致采后损失。因此，开发柿子的高附加值产品备受关注。在本研究中，采用亚洲使用的自然干燥方法对涩柿和甜柿“Rojo Brillante”进行脱水处理。对干燥动力学和理化性质进行了81天的分析。结果表明，在整个干燥过程中，重量、含水量和水分活度随后均下降，且赤道直径减小。所有使用的薄层数学模型均适用于表征两种具有相似行为的产品的干燥特性。涩柿和甜柿样品的有效水分扩散率值分别为5.07×10⁻¹⁰ m²/s和6.07×10⁻¹⁰ m²/s。干燥处理显著降低了可溶性单宁含量，涩柿样品在20天后获得了与甜柿样品相似的值。在干燥期间，涩柿果实的外部和内部果肉均保持橙色，而甜柿果实在干燥57天后出现褐色。因此，无需事先进行脱涩处理。
