Evening Primrose Seed Beverage Processing Technology And Rheology Research

Oenothera biennis, belonging to onagraceae and oenothera category annual or biennial herbaceous plant, is commonly known as sesamum indicium and originally produced in temperate zone of America. It is wild herbaceous plant produced in northeastern provinces of China, especially in Jilin with abundant production and good quality. Its seed is used as it contains 23%--30% unsaturated fatty acid in which 70% is linolenic acid and 30% isγ- linolenic acid essential for human body. γ-linolenic acid(abbreviated as GLA) is all-cis 6,9,12- octadecatrienoic acid and it’s the best among all edible vegetable oils. Oenothera biennis seed is the only plant seed which contains γ- linolenic acid. γ- linolenic acid belongs to unsaturated fatty acid with molecular formula being C18H30O2 and molecular weight being 278. It is an essential fatty acid for human body, and it is insoluble to water while being easily soluble to solvenets like petroleum ether and normal hexane, it is colorless oily liquid under normal temperature with functions of reducing blood fat and blood glucose and so on. At present, oenothera biennis seed is mainly used to extract unsaturated fatty acid in oenothera biennis seed soil which is mainly processed into soft capsule, pills, cream, emulsion, etc. It is applied in treatment of common diseases, like reducing blood fat, blood glucose, cholesterol and so on.This paper, taking oenothera biennis seed in Changbai Mountain area as raw material, researched and developed oenothera biennis seed beverage which abundantly containsγ- linolenic acid. Through study of its processing technology, formula, stability, rheological property and so on, experimental results are as follows:1. Optimal formula of oenothera biennis seed beverage was determined through single-factor experiment and orthogonal experiment as 70% dosage of primary pulp, 10% Soluble solids and 0.15% total acid. Influencing degrees of factors on optimal formula of oenothera biennis seed beverage were ranked as total acidity> primary pulp content > Soluble solids.2. Oenothera biennis seed contained unsaturated fatty acids like protein and γ-linolenic acid, beverage stability could be reached by adding composite emulsion stabilizer. Optimal emulsion stabilizer combination was determined through single-factor experiment and orthogonal experiment as 0.25% xanthan gum, 0.3% CMC, 0.3% sucrose ester and 0.25% monoglyceride. Influencing degrees of factors on emulsion stability of oenothera biennis seed beverage were ranked as xanthan gum > sucrose ester >monoglyceride >CMC.3. To guarantee storage conditions and objective quality characteristics of oenothera biennis seed beverage, this paper studied rheological properties of oenothera biennis seed beverage, and results presented typical pseudoplastic fluid. When shearing rate was 200 s-1 and temperature increased from 10 ℃to 80℃, its viscosity decreased from 0.004 m Pa·s to 0.001 m Pa·s. Viscosity of oenothera biennis seed beverage would experience relatively slight variation as temperature rose, that’s to say, it would be influenced a little by temperature, so it’s of good storage stability.4. The experiment determined technological process of oenothera biennis seed beverage as oenothera biennis seed-smashing-digestion-defibrination with colloid mill-centrifugation-blending-homogenizing-bulkin-sterilization-cooling-inspection-fin ished product. The developed oenothera biennis seed beverage was dark red turbid liquid with tender taste, stable status and specific flavor of oenothera biennis seed, there was no sediment or layering phenomena. Oenothera biennis seed contains richγ-linolenic acid which improves nutrition and health care characteristics of the beverage.