| Dendrobium officinale is a kind of plant with medicine and food homology,which contains polysaccharides,dendrobine,phenols and other active components,and has a long medicinal history in China.Vinegar is a kind of acidic health food,which is widely used as condiment or drink directly.It has the effects of hypoglycemic,antibacterial and antifatigue and so on.The combination of Dendrobium officinale and vinegar can not only give full play to the health care effect of vinegar,but also provide a certain basis for the diversified development of Dendrobium officinale products.In this paper,Dendrobium officinale was used as raw material to improve its polysaccharide content by ultrasonic treatment.The ultrasonic treated Dendrobium officinale pulp and rice saccharified liquid were used as raw materials for alcohol fermentation by yeast and Lactobacillus plantarum,and the fermented mash was used for acetic acid fermentation in two different ways: solid state fermentation(ssf)and liquid state fermentation(lsf).The changes of physicochemical indexes in the fermentation process were explored,and the quality,flavor and functional characteristics of the two kinds of Dendrobium officinale vinegar were analyzed.The main research contents and conclusions are as follows:(1)Ultrasonic treatment was used to improve the polysaccharide content of Dendrobium officinale pulp.On the basis of single factor experiment,taking the polysaccharide content of Dendrobium officinale pulp as the index,the optimum ultrasonic treatment conditions were determined by orthogonal experiment: ultrasonic power was 400 W,ultrasonic temperature was 70?,treatment time was 30 min.under these conditions,the polysaccharide content of Dendrobium officinale pulp was 3.05 g/ L,increased by 30.9% compared with the untreated Dendrobium officinale pulp.(2)The process parameters of alcohol fermentation of mixed strains and different acetic acid fermentation processes were optimized and the changes of physical and chemical indexes in the fermentation process were explored.Through single factor experiment,the optimum amount of Dendrobium officinale pulp was 50%.Based on the single factor experiment,the optimum technological parameters of alcohol fermentation were determined by orthogonal experiment: yeast inoculum was 0.1%,lactic acid bacteria inoculum was 4%,fermentation temperature was 30?.Under these conditions,the alcohol content of fermentation broth was 8.07%vol,and the lactic acid content was 9.21 g/L.The single factor experiment of acetic acid fermentation showed that the total acid content was the highest when the initial alcohol content was 7%vol and the moisture content of brewing mass was 70%.The total acid content of vinegar fermented by ssf and lsf were 4.98 and 5.21 g/100 ml,and the non-volatile acid content was 0.66 and 0.42 g/100 ml.(3)The organic acids,flavor substances and sensory evaluation of Dendrobium officinale vinegar fermented by single strain fermentation,mixed strain fermentation,solid state fermentation and self brewed rice vinegar were compared and analyzed.The results showed that the inoculation of Lactobacillus plantarum could significantly increase the content of lactic acid,increase the types of flavor substances,reduce the relative content of volatile acids,and had a positive contribution to the aroma and taste of vinegar;ssf was beneficial to increase the contents of organic acids except acetic acid,and significantly increase the variety of flavor substances.The sensory scores of aroma,taste and color were higher than those of the other two Dendrobium officinale vinegars.Dendrobium officinale as the raw material of vinegar fermentation,has little effect on the flavor substances of vinegar,but can improve the content of lactic acid to a certain extent.(4)Objective to explore the changes of polysaccharide,total phenol content and antioxidant activity during the fermentation of Dendrobium officinale vinegar.The results showed that the content of polysaccharide showed a downward trend,the total phenol increased in the alcohol fermentation process,and decreased slightly after acetic acid fermentation,and the antioxidant activity increased overall.Compared with single strain fermentation,the inoculation of Lactobacillus plantarum could increase the content of polysaccharides and total phenols in fermentation broth,and improve its DPPH radical scavenging ability and reducing ability,but had little effect on hydroxyl radical scavenging ability.(5)Taking rice vinegar,apple vinegar and mature vinegar as control,the antioxidant,hypoglycemic and bacteriostatic effects of Dendrobium officinale vinegar were compared and analyzed.The results showed that the antioxidant activity of Dendrobium officinale vinegar fermented by lsf was higher than that of rice vinegar,and was close to apple vinegar;the antioxidant activity of Dendrobium officinale vinegar fermented by ssf was similar to that of mature vinegar,and was much higher than the other three kinds of vinegar.The hypoglycemic effect of mature vinegar was slightly higher than that of Dendrobium officinale vinegar fermented by ssf.Dendrobium officinale vinegar fermented by lsf and apple vinegar had their own advantages and disadvantages,but they were significantly higher than that of rice vinegar.The results of antibacterial test showed that the Dendrobium officinale vinegar fermented by ssf had a good inhibitory effect on Escherichia coli and Staphylococcus aureus,its inhibitory effect on Staphylococcus aureus was stronger than the other four kinds of vinegar,and its inhibitory effect on Candida albicans was not obvious;the Dendrobium officinale vinegar fermented by lsf also had a certain inhibitory effect on the two kinds of bacteria,and its inhibitory effect was generally lower than that of mature vinegar and rice vinegar,but higher than that of apple vinegar. |
PDF Full Text Request