不同干燥方式对莲藕脆片品质的影响

Effect of Different Drying Methods on Quality of Nelumbo nucifera Gaertn Products

为明确休闲莲藕脆片的最佳干燥方式,采用热风干燥、真空微波干燥、热风-真空微波干燥、热风-气流膨化干燥、真空微波-气流膨化干燥、热风-真空微波-气流膨化干燥6种不同的干燥方式对莲藕片进行干燥后,对所得脆片的色泽、收缩率、硬度、脆度、VC保留率、多酚保留率以及微观结构等品质指标进行分析。结果表明:热风干燥对莲藕脆片色泽影响不大,但硬度过低,脆度差,VC和多酚损失最为严重;真空微波干燥莲藕脆片VC和多酚保留率高,脆性好,但硬度过高,产品皱缩严重,色差和褐变度高;4种不同联合干燥方式生产的莲藕脆片品质较单一干燥的产品均有所改善,其中,热风-真空微波-气流膨化干燥的莲藕片收缩程度和褐变程度较真空微波干燥显著降低,而VC和多酚保留率较热风干燥显著升高,硬度、脆度均适中,多孔性好。综上所述,热风-真空微波-气流膨化干燥是最适宜加工莲藕休闲脆片的方法。

In order to obtain the optimum drying method to product Nelumbo nucifera Gaertn chips, the effects of 6 dryingmethods including hot air drying, vacuum microwave drying, hot air-vacuum microwave combination drying, hot air-explosion puffing combination drying, vacuum microwave-explosion puffing combination drying and hot air-vacuum microwave-explosion puffing combination drying on physico-chemical properties （color, shrinkage, hardness, crispness, vitamin C, polyphenol and micro-structure） of dried Nelumbo nucifera Gaertn were investigated. The results showed that hot air drying had little effect on the color of Nelumbo nucifera Gaertn chips, but the hardness and crispness were the worst, vitamin C and polyphenols were damaged gravely; vacuum microwave-dried lotus root chips had the highest retention of vitamin C and polyphenols, crispness was moderate, but its hardness, crimp, AE and browning degree were not preferable; Compared with single dried-products, the qualities of the four kinds of combination-dried lotus root chips were improved. And shrinkage and browning degrees of hot air-vacuum microwave-explosion puffing combination-dried lotus root chips were significantly lower than vacuum microwave-dried products; vitamin C and polyphenols retention of this drying method had an obvious advantage over hot air drying; hardness and crispness of crisp were moderate and organizational structures were porous. Overall, hot air-vacuum microwave-explosion puffing combination drying method was the most suitable way for processing Nelumbo nucifera Gaertn chips among all the six drying methods.