养殖场除臭酵母发酵条件的优化

为了规模化生产除臭酵母菌JM-1,以菌体活菌数为指标,通过单因素试验和正交试验对其发酵条件进行了优化。结果表明:酵母菌JM-1的最佳发酵条件为:培养温度30℃,初始pH值 5.0,接种量4%,500 mL三角瓶装液量150 mL。在此条件下培养24 h,酿酒酵母的发酵菌数超过7.42×10^8 CFU/mL,与优化前的6.11×10^8 CFU/mL相比较,活菌数提高了21.1%。

Comparison of 3 M^TM Petrifilm^TM Aerobic Count Plates with Pour Plates for Determination of Aerobic Plate Counts in Fermented Chile Mash

Fermented chile pepper mash is a major food product in New Mexico. There are few reports on the fermentation process or on methods to monitor it, In the current study we examined a pour plate procedure with an overlay using plate count agar and 3 MTM PetrifilmTM Aerobic Count （AC） plates for determination of total aerobic bacterial counts during the fermentation of chile mash. Fifty chile mash samples were obtained directly from commercial fermentation vats and examined within 2 h of collection. Serial dilutions of the chile mash were prepared in Butterfield＇s Phosphate Buffer. 1 mL portions of the diluted samples were aliquoted in duplicate onto the AC plates and into empty Petri dishes. Plate count agar was poured and once the plates had solidified, they were overlaid with about 10 mL of PCA to minimize spreaders. Plates were incubated at 30 ℃ for 48 h and enumerated. Paired difference tests were conducted on log transformed data to compare the results of the two plating procedures. For commercial chile mash samples, we did not show any significant differences between the AC plate counts and the pour plate counts （α = 0.05）, 3 MTM PetrifilmTM AC plates are a good alternative to pour plates for the determination of the total aerobic counts in fermented chile mashes.

Characterization of Fresh Cheese with Addition of Probiotics and Prebiotics

Sensorial and microbiological characteristics of a Brazilian fresh cheese samples with Bifidobacterium animalis subps. lactis as well as samples with this probiotic and polydextrose, a prebiotic ingredient, were evaluated. The addition of this microorganism was studied as： （1） lyophilized probiotic added to cheese curd and （2） by using milk previously fermented by this probiotic to produce the cheese. Cheese samples were microbiologically characterized after 0, 7, 14, 21 and 28 days of storage at a temperature of 4 ℃. The microbiological analyses conducted were quantification of total lactic acid bacteria, mesophilic microorganisms, Bif. animalis subps, lactis, coliforms at 30 ℃ and 45 ℃. Affective sensory test was conducted for two different cheese samples （with probiotic and with probiotic and prebiotic） as well as for control one week after manufacturing date. Cheese samples provided acceptable results for coliform counts at 30 ℃ and 45 ℃ in compliance with legislation. The cheese samples produced using milk fermented by probiotic showed counts of 107-108 CFU/g after 28 days of storage, which assures functional property for this product to be claimed.

Selection of Lactobacillus Strains for Functional Whey-Based Beverage Production

The aim of this study was selection of appropriate Lactobacillus strains for production of functional whey-based beverage. Sixteen strains of different species of Lactobacillus genera were studied and their abilities to carry out fast production of the beverage with satisfactory fermentation parameters were assessed. Preliminary screening was performed by evaluating volumetric productivity of tested strains after 24 h of the fermentation. Further selection was based on determining beverage production parameters such as fermentation time, titratable acidity, cell number and sensory characteristics. The strains showed remarkable differences in cell number and sensory properties, which were particularly useful in the selection. Based on the obtained results, the strains Lb. casei ssp. casei ATCC 27139 and Lb. johnsonii NRRL B-2178 are good candidates for the beverage production. These strains are rather similar in terms of beverage production ability, but strain Lb. johnsonii NRRL B-2178 is a top candidate for functional whey based beverage production. This strain attained titratable acidity of 9.2 °SH after 10 h of fermentation, appropriate odor and cell number of 6.8 log （CFU mL-1）.

Effect of Garlic Paste Added to Yoghurt of Cow Milk

Yoghurt has greater popularity among fermented milk products. The development of fruit and fiavoured yoghurt resulted in this product of major importance in markets. Garlic is a common food spice and herbal medicine for preventing of many human diseases. This study was conducted to analyze physicochemical properties of yoghurt by incorporating of garlic paste at different concentrations. Yoghurt mixtures were prepared with 0.5%, 1%, 2% and 3% garlic paste, and without garlic paste as a control. They were subjected into chemical, sensorial and microbial assessment during the storage period of four weeks. At the first week, the chemical attributes, such as ash, dry matter, total sugar, reducing sugar and pH show significantly （P 〈 0.05） higher in 3% garlic added yoghurt. On the other hand, titrable acidity was higher in yoghurt made without garlic paste. At the fourth week of storage period, 3% garlic added yoghurt received higher mean value for ash, dry matter, total sugar, reducing sugar and pH. Similarly, yoghurt made without garlic received higher mean value for titrable acidity. Garlic reduced the bacterial load in the yoghurt, as bacterial count was decreased with increase in the concentration of garlic paste. Finally, organoleptic assessment revealed that there were （P 〈 0.05） changes among the treatments in the sensory attributes. Although, yoghurt made from 1% of garlic at the first week of storage showed the best overall acceptability compared with other all treatments, such as values of ash, dry matter, total sugar and reducing sugar were 0.61%±0.05%, 14.73% ± 3%, 12.7% ± 1.57% and 1.86% ± 0.19%, respectively.

Optimization of Parameters for Fermentative Production of Virgin Coconut Oil by Lactobacillus fermentum NDRI 141

Commercially, many methods are adopted for the production of the Virgin Coconut Oil （VCO）. Nowadays, natural fermentation is widely employed to produce VCO in wet processing. But the problem in natural fermentation process has much contamination, due to surplus micro organisms present in natural environment, which leads to the poor quality of VCO. To overcome this, usage of probiotic organism like Lactobacillus fermentum is more beneficial for the fermentative production of VCO. Fermentation studies were conducted scientifically in computer controlled bioreactor to determine the effect of pH, temperature, inoculum concentration, oxygen requirement and incubation time on the yield of VCO. Yield efficiency of VCO in each parameter was determined. The pH of 5± 0.1, temperature at 45 ± 0.1 ~C, inoculum concentration of 2%, fermentation end time of 48 hrs and microaerophilic conditions are the most suitable parameters for the superior production of VCO.