Study On The Extraction Technics Conditions And Characteristics Of Dietary Fiber From Citrus Peel By Fermentation With Lactobacillus And Trichoderma Viride

In this paper, four kinds of citrus peels—Citrus grandis Osbeck, Citrus unshiu Marc, Citrus reticulate Blanco, Citrus sinensis which are common in Sichuan—were taken as raw material, and we studied the extraction process and physical and chemical property of dietary fiber(DF) from citrus peel by Lactobacillus and Trichoderma viride. Also the optimum bleaching technology of DF products fermented by Trichoderma viride was investigated in order to provide theoretical evidences and technical guides for the comprehensive utilization and lay experimental basis for the industrial production of citrus peel. The main results as follows:1. Single factor test showed that the cotent of total dietary fiber (TDF) was mainly affected by the inoculation amount of starter, temperature,time and pH value. The orthogonal test L₉ (3⁴) was performed to determine the optimum technics for DF from the citrus peel by Lactobacillus as follows: the inoculation amount of starter was 3%,the temperature was 40℃, the time was 20h and the pH value was 6.8; and the optimum technics for DF from the citrus peel by Trichoderma viride as follows: inoculation amount of starter was 10%,the temperature was 24℃,the time was 52h and the pH value was 6.8.Under these conditions,compared with the raw powder,the TDF content significantly increased.2. The orthogonal test L₉ (3⁴) was performed to determine the optimum technics for the blenching technology of DF products from citrus peel fermented by Trichoderma viride as follows: the H₂O₂ was 5%, the temperature was 45℃, the time was 2h and the pH value was 10. The influence of the four factors on the blenching of them were in order of temperature,time,pH and H₂O₂.3. The fermentation DF products of Citrus grandis Osbeck, Citrus unshiu Marc, Citrus reticulate Blanco, Citrus sinensis fermented by Lactobacillus were analyzed to be Water holding capacity respectively as 13.39,10.68,9.29 and 11.29ml/g and Swelling capacity as 9.12,8.95,9.89 and 9.06g/g;and the fermentation DF products of Citrus grandis Osbeck, Citrus unshiu Marc, Citrus reticulate Blanco, Citrus sinensis fermented by Trichoderma viride were analyzed to be Water holding capacity respectively as 9.88,7.33,5.90 and 7.02ml/g and Swelling capacity as 11.96,13.92,14.15 and 13.14g/g. 4. As for the abiding of heavy metals under pH2.0(nearly gastric pH value),the fermentation DF products of citrus peel had low capacities for Cu²⁺,but had well capacities for Pb²⁺ and Cd²⁺.The capacities of abinding Cu²⁺ of the fermentation DF products of Citrus grandis Osbeck, Citrus unshiu Marc, Citrus reticulate Blanco, Citrus sinensis fermented by Lactobacillus were respectively as 28.82,26.46,29.33 and 28.15μmol/g,for Pb²⁺ as 42.36,39.54,37.66 and 40.23μmol/g,for Cd²⁺ as 32.89,33.65,34.36 and 36.14μmol/g; the capacities of abinding Cu²⁺ of the fermentation DF products by Trichoderma viride were respectively as 29.13,27.64,28.06 and 28.02μmol/g,for Pb²⁺ as 43.87,41.39,38.91 and 42.68μmol/g,for Cd²⁺ as 34.25,32.16,39.68 and 36.09μmol/g.5. The H₂O₂ scavenging capacities of the fermentation DF products of Citrus grandis Osbeck, Citrus unshiu Marc, Citrus reticulate Blanco, Citrus Sinensis fermented by Lactobacillus were respectively as 28.57%,30.95%,30.95% and 22.86%;and the results of the DF products Trichoderma viride were respectively as 18.14%,30.19%,28.57% and 16.62%.As discussed above,the quality of DF from citrus peel was improved through the processing with fermentation. The fermentation technics is simple and low in cost, which laid a solid foundation for further large-scale industrial production. Through comparative analysis,we found that compared with Trichoderma viride fermentation method,the Lactobacillus fermentation method was more suitable to be an effective measure for recycling and comprehensive utilization of citrus peel.