Effect of Thermal Processing on Phenolic Content, Tocopherols and Antioxidant Activity of Sacha Inchi Kernels

Abstract

Raw, honey-coated and processed Sacha inchi kernels were investigated for effects of different thermal processes on the content of total phenolic content (TPC) (Folin assay) and radical scavenging capacity (DPPH method), the content of α-tocopherol, ß + γ-tocopherol, δ-tocopherol. Sacha inchi kernels were subjected to open boiling, pressure boiling, sous-vide, low-temperature roasting, high-temperature roasting and honey roasting. The radical scavenging capacity of kernels was little affected by thermal processing, with the average loss of 8%. Roasting had a significant negative effect on tocopherol content but not on the total phenolic content. The appropriate thermal procedure and adequate time can significantly influence the quality of Sacha inchi kernels during food preparation. Especially roasting at 190C for 35 min and honey roasting at 170C for 30 min of Sacha inchi kernels have positive effect of increasing TPC. Practical Applications Plukenetia volubilis or Sacha inchi seeds are the traditional food used as nuts in the mountain area of the South America. The oil have recently become popular as a source of unsaturated fatty acids, antioxidants and A and E vitamins; however, not much information has been published on the micronutrients in processed seeds. This article presents several processing methods for Sacha inchi seeds and offers the description of changes in health beneficial compounds the kernels are seeking for. This article aims to become a useful tool for increasing number of importers and processors spreading this rediscovered food.