Effects of five drying methods on the drying characteristics and quality of peanuts
摘要
ObjectiveTo determine the appropriate mechanical drying technology for peanuts.MethodsFresh peanuts were used as raw materials. The effects of heat pump drying (HPD), far infrared drying (FID), electric heating drying (EHD), far infrared combined heat pump drying (FI-HPD), and natural drying (ND) on drying time, unit energy consumption, drying rate, nutritional quality, color, texture, and germination rate were compared and analyzed.ResultsDuring the four mechanical drying methods, the moisture ratio and drying rate of peanuts decreased with the prolongation of drying time, and the drying process was a falling-rate drying phase. Among these, the FI-HPD group had the shortest drying time and the lowest unit energy consumption. The drying method significantly affected the content of protein, oleic acid, and linoleic acid (P<0.05), but had no significant effect on fat content. After the four mechanical drying methods, the protein content in peanuts was higher and the oleic acid content was lower in the EHD and FI-HPD groups. The drying method also significantly affected the color, hardness, and adhesion of peanuts (P<0.05). After mechanical drying, the acid value was 0.75~2.00 mg/g, and the peroxide value was 0.03~0.14 mg/g, both conforming to national standards. After the four mechanical drying methods, the germination index of peanuts decreased to some extent, with the FI-HPD group showing the greatest reduction in germination rate and germination potential. The germination index of the HPD and FID groups was higher than 90%.ConclusionFI-HPD is suitable for the drying processing of edible peanuts, while HPD and EHD are suitable for the drying processing of peanut seeds.