Analysis of Capsaicinoids from Hot Red Pepper Powder by Near-Infrared Spectroscopy

Hot pepper is widely used as seasoning on Asian countries. Especially, South Korea has various kinds of hot pepper food product such as various Kim-chis, hot pepper pastes, soups, and other dishes. Those contain sliced or powdered hot pepper to enhance hotness in dishes. As Korean food getting popular in world wide, the content of hotness needs to be measured and controlled. Capsaicinoids is a chemical material which contributes to hotness of pepper. Quantitative analyze method on capsaicinoids needs extraction, separation, and HPLC (high performance liquid chromatography) analysis. It is time consuming, expensive, and expert needed method which is not appropriate to apply during online food process. Therefore, to analyze in easy and fast way, near-infrared analysis on capsaicinoids from hot red pepper was conducted. 14 kinds and 10 of each kind of red hot pepper, totally 140 samples were powdered and sieved into 500um particle. Those of half were mixed with seeds and the other was not. Reflectance (892~1695nm) spectrum of those powder were acquired with specially made probe holder. Capsaicinoids' concentration was analyzed conventional method. Data preprocessing such as baseline correction and 1st derivative were conducted before PCR (principal component regression) and PLSR (partial least square regression) analysis and cross validated. Determination coefficient of validation showed 0.9702 and 0.9029; SECV as 23.65 and 43.05 respectively to PCR and PLSR.