不同干燥技术对鲜切枣片品质的影响
Influence of different drying methods on the quality of the slices of Zizyphus jujuba
-
摘要: 探究6种不同干燥方式对红枣切片体积密度、复水性、总酮含量、总酚含量、色泽变化与挥发性成分等品质的影响。结果显示,真空冷冻干燥样品复水性、总酮含量、总酚含量和挥发性成分种类均最高,亮度(61.92±0.44)和总色差(0.67±0.14)与原枣片没有明显差异,但挥发性成分中乙酸含量较高,约占总成分的41.55%,说明除较小的风味影响外,冷冻干燥样品品质最佳。间歇微波干燥相比连续微波干燥样品的总酮、总酚含量明显增高(p<0.05),而亮度值增大2.39,总色差减少2.68,表明两种真空微波干燥样品品质差异较小,间歇式加热可以避免样品集中受热导致营养素过度氧化或降解。常压干燥技术(热风、红外与间歇微波),容易引起热氧化或降解,导致酮类、酚类成分含量降解到原枣片的55%左右,亮度值下降到51.79,挥发性成分种类约占原枣片的60%,并且会生成异味成分如糠醇、糠醛等,枣片干燥品质较差。然而,常压干燥技术能提高红枣特征色泽,减弱乙酸增长量(热风干燥乙酸含量仅上升15.68%)。因此,可综合考虑各项干燥方法,形成复合干燥技术,实现优势互补。该研究为鲜切枣片的干燥及干燥技术的提升,提供了基础数据。Abstract: To study the influence of different drying methods on quality of the slices of Zizyphus jujuba, the volume density, rehydration characteristics, the total content of ketones and phenols, the colour and the volatile components were analyzed respectively.The results showed that rehydration characteristics, the total content of ketones and phenols, and the total number of volatile components were maximum in slices by FD. Meanwhile, there was no significant difference between the brightness ( 61.92 ± 0.44) and chromatic aberration ( 0.67 ± 0.14) and that of control. However, the off-flavor component ( acetic acid) content was so high ( 41.55% ± 4.64%) . There were significant differences in total content of ketones and phenols between IMVD and CMVD ( p < 0.05) . The brightness increased by 2.39 and chromatic aberration fall by 2.68 of the slices by IMVD compare to CMVD due to the excessive thermal treatment. It could easily lead to oxidation and degradation by HAD, IR and IMD, so the total content of ketones and phenols and the number of volatile components fall beyond 55% with producing offflavor components such as furfuralcohol and furfural.The brightness of slices falled to 51.79.Nevertheless, the three drying methods could improve intensity of redness and control formation of acetic acid.So it can develop compound-drying technology to realize advantageous complementarities.It provided basic data for further study on drying methods of the slices of Zizyphus jujuba.