不同干燥方式对黄秋葵脆条品质及能耗的影响

为确定休闲型黄秋葵脆条的最佳干制方式,研究比较了远红外干燥、热风干燥、真空冷冻干燥、真空微波干燥、真空冷冻联合真空微波干燥和热风联合真空微波干燥对黄秋葵脆条的硬度、脆度、色泽、收缩率、干燥时间、能耗率以及总黄酮、总酚和多糖含量的影响。结果表明:真空冷冻干燥黄秋葵脆条总黄酮、总酚及多糖含量均最高,但口感绵软、不酥脆,且干燥时间最长,能耗最高;远红外干燥、热风联合真空微波干燥和热风干燥脆条的总黄酮、总酚及多糖含量依次降低,这三种干燥脆条均色泽差、硬度大、收缩严重;真空冷冻联合真空微波干燥与真空微波干燥脆条的硬度适中、酥脆度较佳,且总黄酮、总酚及多糖含量仅次于真空冷冻干燥脆条,两种干燥方式下黄秋葵脆条的质构及营养物质含量差异不显著(p>0.05),但真空冷冻联合真空微波干燥时间是真空微波干燥的40倍,能耗率约是其5倍。综合看来,真空微波干燥脆条的硬度、脆度、色泽和营养成分保持较好,且干燥时间短、能耗低,较适宜于休闲型黄秋葵脆条的干制加工。 

Effect of drying methods on quality and energy consumption of okra crisp bar

In order to choose the best drying method for okra crisp bar,the effects of different drying methods including FID,AD,FD,MVD,FD-MVD,and AD-MVD on hardness,crispness,color,shrinkage,drying time,energy consumption as well as total flavonoid content,total phenolic content and polysaccharide content of okra crisp bar were investigated.The results showed that FD exhibited the highest retention of flavonoids,total polyphenol and polysaccharide,but poor hardness and the longest drying time and energy consumption.FID,AD and AD-MVD samples exhibited the content of flavonoids,total polyphenol and polysaccharide reduced in turn.Moreover,the hardness,color and shrinkage of the samples dried by the three drying methods were worse.FD-MVD and MVD samples showed higher retention of flavonoids,total polyphenol and polysaccharide next to FD samples as well as moderate hardness and better crispness. The differences of texture and nutrient content between MVD and FD-MVD dried samples were insignificant( p>0.05),but the drying time and energy consumption of FD-MVD were 40 and5 times that of the MVD samples,respectively. Overall,MVD may be a suitable industrial-scale processing method for okra crisp bar in consideration of better product quality and lower energy consumption.