T<span>he effects of varying the ratio of ice cream mix to whole milk yogurt on the characteristics of the mixes and the resulting frozen products including their ice cream and frozen yogurt controls were invest...T<span>he effects of varying the ratio of ice cream mix to whole milk yogurt on the characteristics of the mixes and the resulting frozen products including their ice cream and frozen yogurt controls were investigated. Ratios of ice cream mix to yogurt included 100% yogurt for the frozen yogurt control, 25% ice cream mix and 75% yogurt, 50% ice cream mix and 50% yogurt, 75% ice cream mix and 25% yogurt, and 100% ice cream mix for the ice cream control. The resulting mixes were sampled for analysis of total solids content, fat content, pH, and viscosity and then frozen in a batch freezer. The frozen products were analyzed for MRS lactobacilli counts, rate of meltdown at 21°C (volume after 1 h and time for 15 mL to melt), and sensory properties (flavor and body/texture). The total solids contents ranged from 11.89% to 39.65%, and the fat contents ranged from 2.8% to 12.6% for the 100% yogurt and 100% ice cream mixes, respectively. The pH ranged from 4.55 for the 100% yogurt to 6.77 for the 100% ice cream mix. The 100% yogurt sample had the highest viscosity. As expected, the 100% yogurt and the 75% yogurt samples had the highest MRS lactobacilli counts. The rate of meltdown increased with the increasing proportion of ice cream in the yogurt ice cream. The frozen products consisting of 75% and 100% ice cream received the highest flavor scores and body/texture scores. Yogurt ice cream made from 75% ice cream usually had more desirable meltability and sensory properties than yogurt ice creams made from either 25% or 50% ice cream and provides an opportunity for delivering a desirable product that has a healthy imag</span>e.展开更多
Lactobacillus delbrueckii ssp. bulgaricus is a widely used bacterium for the production of some fermented dairy products. Mild sonication intensity condition is a non-destructive technique that uses sound waves to cau...Lactobacillus delbrueckii ssp. bulgaricus is a widely used bacterium for the production of some fermented dairy products. Mild sonication intensity condition is a non-destructive technique that uses sound waves to cause cavitation in aqueous solutions and may improve the permeability of membranes, speed up the transfer of substrates and promote cellular growth and propagation. The objective was to determine the effect of mild sonication intensities at different temperatures on growth, bile tolerance and protease activity of Lactobacillus delbrueckii ssp. bulgaricus LB-12. The treatments were four sonication intensities (8.07, 14.68, 19.83 and 23.55 W/cm2) randomized at three different temperatures (4℃, 22℃ and 40℃). The energy input (1500 J) was kept constant in all treatments. Control samples did not receive any sonication treatment. Growth and bile tolerance were determined every 2 h for 12 h of incubation. Protease activity was determined at 0, 12 and 24 h. Mild sonication conditions included 1) mild sonication intensities, 2) temperatures and 3) times, all three of which played a role in influencing the desirable attributes of Lactobacillus delbrueckii ssp. bulgaricus LB-12. Of all the mild sonication intensities studied, 14.68 W/cm2 had the best overall influence at certain time points forimproving the bile tolerance and growth at 4℃ and protease activity at 40℃. Mild sonication intensity of 23.55 W/cm2 had the best overall influence at certain time points for protease activity of at 22℃. Some mild sonication conditions could be recommended for improvement of some characteristics of Lactobacillus delbrueckii ssp. bulgaricus LB-12.展开更多
文摘T<span>he effects of varying the ratio of ice cream mix to whole milk yogurt on the characteristics of the mixes and the resulting frozen products including their ice cream and frozen yogurt controls were investigated. Ratios of ice cream mix to yogurt included 100% yogurt for the frozen yogurt control, 25% ice cream mix and 75% yogurt, 50% ice cream mix and 50% yogurt, 75% ice cream mix and 25% yogurt, and 100% ice cream mix for the ice cream control. The resulting mixes were sampled for analysis of total solids content, fat content, pH, and viscosity and then frozen in a batch freezer. The frozen products were analyzed for MRS lactobacilli counts, rate of meltdown at 21°C (volume after 1 h and time for 15 mL to melt), and sensory properties (flavor and body/texture). The total solids contents ranged from 11.89% to 39.65%, and the fat contents ranged from 2.8% to 12.6% for the 100% yogurt and 100% ice cream mixes, respectively. The pH ranged from 4.55 for the 100% yogurt to 6.77 for the 100% ice cream mix. The 100% yogurt sample had the highest viscosity. As expected, the 100% yogurt and the 75% yogurt samples had the highest MRS lactobacilli counts. The rate of meltdown increased with the increasing proportion of ice cream in the yogurt ice cream. The frozen products consisting of 75% and 100% ice cream received the highest flavor scores and body/texture scores. Yogurt ice cream made from 75% ice cream usually had more desirable meltability and sensory properties than yogurt ice creams made from either 25% or 50% ice cream and provides an opportunity for delivering a desirable product that has a healthy imag</span>e.
文摘Lactobacillus delbrueckii ssp. bulgaricus is a widely used bacterium for the production of some fermented dairy products. Mild sonication intensity condition is a non-destructive technique that uses sound waves to cause cavitation in aqueous solutions and may improve the permeability of membranes, speed up the transfer of substrates and promote cellular growth and propagation. The objective was to determine the effect of mild sonication intensities at different temperatures on growth, bile tolerance and protease activity of Lactobacillus delbrueckii ssp. bulgaricus LB-12. The treatments were four sonication intensities (8.07, 14.68, 19.83 and 23.55 W/cm2) randomized at three different temperatures (4℃, 22℃ and 40℃). The energy input (1500 J) was kept constant in all treatments. Control samples did not receive any sonication treatment. Growth and bile tolerance were determined every 2 h for 12 h of incubation. Protease activity was determined at 0, 12 and 24 h. Mild sonication conditions included 1) mild sonication intensities, 2) temperatures and 3) times, all three of which played a role in influencing the desirable attributes of Lactobacillus delbrueckii ssp. bulgaricus LB-12. Of all the mild sonication intensities studied, 14.68 W/cm2 had the best overall influence at certain time points forimproving the bile tolerance and growth at 4℃ and protease activity at 40℃. Mild sonication intensity of 23.55 W/cm2 had the best overall influence at certain time points for protease activity of at 22℃. Some mild sonication conditions could be recommended for improvement of some characteristics of Lactobacillus delbrueckii ssp. bulgaricus LB-12.
