Research On The Processing Technology Of Clarified Yacon Juice Concentrate

Yacon had wide market development prospects according to its medicinal value and health care effect, the yacon juice concentrate had just started to develop. Yacon had a high polyphenol content, and yacon also contains a large number of molecules in the gel-type substances, so the yacon juice concentrate was dark brown, low light transmittance, and poor commercial quality. In order to promote the commercial exploitation of yacon products, color protection and clarification process was studied to improve the quality of yacon juice concentrate and provide theoretical guidance for the corporation.Color protection process of yacon juice was studied for preventing browning while beating. Citric acid, tartaric acid, ascorbic acid, sodium ascorbate, sodium chloride, disodium ethylene diamine tetraacetate, disodium stannous citrate were choosed, with△E as evaluation indexes, the effect of antibrowning agents and blanching for color protection was discussed. The result indicated that citric acid and ascorbic acid has better color-preservation effect, the blanching can make the enzyme inactive and the color can keep for a long time; the combination result was 1 % citric acid and 0.6 % ascorbic acid, combined with blanching for 2 min were better to keep the bright yellow color of fresh yacon.The clarification process of yacon juice was investigated. The clarification methods of ethanol and chitosan were studied with the parameter of light transmittance, contents of protein and total phenolic compounds, and the clarification effect of ethanol, ultrafiltration and chitosan was compared with anlysis the parameter such as light transmittance, contents of protein and total phenolic compounds, total sugar, reducing sugar and constituent of sugar. The results showed that the transmittance of 60 % ethanol standing for 3 h at 4℃, 1 % chitosan at 50℃for 30 min and ultrafiltration with 10000 MWCO membrane was over 80%.The polyphenol content of the juice concentrate was ethanol>chitosan>ultrafiltration. The protein content decreased from 84.65μg/mL to less than 20μg/mL, ultrafiltration can get the lowest 4.27μg/mL. Ethanol have a great impact on the reduce sugar. The total sugar concent was ethanol>ultrafiltration>chitosan.With yacon juice concentrate as raw material, the formula of the beverage was as follow: 6 % yacon concentrate, 5 % sucrose, 0.1 % citric acid, 0.2 % Sodium carboxymethyl cellulose. The beverage had better mouthfeel, good appearance. The beverage did not appear precipitation for a long time, so the yacon juice concentrate had a good quality and high stability.