Reserch On Bacterial Cellulose Fermentation Productive Form Fruit Juices

Bacterial cellulose (BC) has many unique properties, high hydrophilic, largewater-holding ability, gelatin properties, stability etc. As a new functional food material, ithas a strong attraction. In addition, BC also can improve the digestive system environment,prevent constipation, clear bowel poison, reduce cholesterol, lose weight, resist cancer andanti-aging. With the grow of living standard and chang of food structure, the acceptable dailyintake of dietary fiber is obviously inadequate. So develop edible BC has practicalsignificance for developing distinctive functional foods. But the low output and the high costsof BC production, the application of BC had large limit. The focus of research are improveBC yield and reduce production costs.First, this research compared Gluconacetobacter hansenii J₂to M₄38in yield andstructural properties of BC producing by them. Then used the strains which had high yieldusing fruit juices produce BC, discussed fruit juices as the fermentation medium influencedon the BC yield. Finaly, used pineapple wine as fermention medium, optimized pineapplewine fermention medium, obtained optimum component of medium. Some results asfollows:(1) Observed the individual and colony form, discovered that the strains M₄38and J₂have the same individual form, but the colony form of M₄38were more intensive and thevolume lager.(2) Analysed the yield, thickness, water content, rehydration rate, cellulose content,protein content, fat content, water holding capacity and water release rate of BC producing byM₄38and J₂, showed that the properties of BC from M₄38were batter than J₂. The properties ofBC from M₄38were37.88g/100mL,1.416cm,98.78%,84.53%,89.72%,7.73%,1.59%,105times,80h,respectively; BC from J₂were15.94g/100mL,1.17cm,98.67%,83.69%,88.58%,7.58%,1.56%,94times,56h, respectively。(3) The cellulose content of BC producing by J₂and M₄38were very higher, and thecrystalinity were78.6%and82.2%respectively, the content of fiber I_αwere52.13%and62.03%respectively, the maximum tensile strength were55.8MPa and78.4MPa respectively.(4) Using apple juice, pear juice, pineapple juice and watermelon juice as raw materials,M₄38as the fermentation strains to produce BC. Discovered that add1.6%,1.4%,1%and 0.3%yeast extract to apple juice, pear juice, pineapple juice and watermelon juicefermentation medium respectively, the yield of BC could reach the highest, were33.818g/100mL,46.343g/100mL,44.296g/100mL and62.147g/100mL respectively, andwere1.41times,1.43times,1.25times and1.35times than absolutejuice fermentationmedium respectively. The highest yield of BC produced by watermelon juice medium.Analysis the structure and properties of BC produced by fruit juice medium, results showedthat there be difference in rehydration rate, cellulose content, sugar content and fat contentof dry BC membrane among four different fruit juice mediums; But in water content of wetBC membrane and protein content of dry BC membrane were indifferent.This declared that watermelon juice is a natural and high-efficiency raw material forproducing BC membranes, and the BC membranes were strong and elastic, also had goodhydrophilic and water binding capacity, as the edible materials apply to produce foods arerich in dietary fiber.(5) Using RSM to optimize pineapple wine fermentation medium of M₄38, the optimalfermentation medium is: yeast extract0.7%, K₂HPO₄·3H₂O0.05, MgSO₄·7H₂O2.0%,FeSO₄·7H₂O0.06%, ZnSO₄·7H₂O0.3%, citric acid0.03%, Ethanol absolute0.94%, comparewith initial fermentation medium, the yield of BC enhanced3.10times.