| In recent years, ice-cream products become one of the most rapidly developing products after the beverages and instant noodles. Soft ice-cream is very popular by consumers. Frozen food is included in the highly nutritious and quality food nowadays, and consumers pay more attention to their own health, the low calorie and probiotic-containing health products will attract more consumers. Based on skim milk powder, sugar, butter, emulsifier, stabilizer, synanthrin, maltodextrin as materials, making soft ice cream contains active probiotic low calories, via texture evaluation, rheological characteristics and nutritional composition evaluation, the nutritional health care function of probiotic-containing soft ice-cream was researched and evaluated. The main results are as follows:1 The process optimization of soft ice-cream mixesFirst, by using single factor experiment selecting the addition of skim milk powder, white sugar, milk fat, stabilizer, emulsifier, maltodextrin, synanthrin, as single factors of orthogonal experiment optimization with L18(37) table, by the analysis of range from the L18(37) table, we obtained the best optimization was as follow:skim milk powder 12%, white sugar 8%, butter and the cream 9%, stabilizer 0.35%, emulsifier 0.4%, maltodextrin 2%, synanthrin 3%, and by verifying experiment proved that the soft ice-cream tastes best.2 The fermentation process optimization of probiotic-containing soft ice-cream mixesOn the basis of the best formula, first using single factors experiment to discuss the factors influenced the quality of fermentation ice-cream mixes via inoculation quantity, fermentation ti-me, and fermentation temperature, then according to single factors experiment proceeds of best range, using Box-Behnken design, taking the total number of probiotics and the sensory score as response value by using response surface analysis to obtain the optimize fermentation conditions. Finally, obtained the fermentation conditions:inoculation 3.7%, fermentation temperature 42 ℃, fermentation time 5h, under these conditions, we obtained the best quantity of ice-cream, and the average number of probiotics is 7.56×106cfu/mL, sensory score is 88.5.3 The correlation between texture and sensory evaluation of probiotic-containing soft ice-creamUsing TPA test and sensory evaluation methods, evaluate 3 sold samples and homemade sample with texture and sensory, and analyze the relevance of TPA method and the sensory evaluation factors. Three principal components of sensory evaluation were extracted by principal component analysis. And the cumulative contribution of variance is 80.109%, so that it can completely explain the firmness, consistency, melting degree in the mouth. It can be seen that there are many of the sensory evaluation indexes, but the firmness, consistency, melting degree in the mouth take the leading role. The correlation between the sensory indexes of homemade soft ice-cream is existing, and most of the TPA analysis parameters also exist different degree of correlation:Sensory evaluation of firmness, ice-feeling, smooth degree has strong correlation with TPA test indexes. Therefore, the firmness, ice-feeling, and smooth degree can be described by the TPA model.4 Analysis of rheological characteristics of probiotic-containing ice-cream mixesUsing HAAKE MARS Ⅲ rheometer to investigate the rheological characteristics of 4 samples, measurements as steady shear flow, shear structural recovery, and thermostabl e property were carried out to study fluidity, thermal stability and macromolecular networ k structure of ice-cream mixes. The result showed that all samples were pseudoplastic flu id with thixotropy, Shear thinning occurs when the shear rate increases, the shear thining of homemade ice cream mixes was stronger than other samples. The shear stress of the mixes increased with the increase of the shear rate, but the difference between homema de sample and other samples is large. The shear recovery of sample 3 is the best, and t he difference of the shear recovering ability between the samples is small. The thermal s tability of each sample was as follows:sample 1> sample 2> sample 3> home-made sample. The effect of temperature on the viscosity of homemade ice cream mixes is the largest, fluidity is strong. When the temperature increases, the ice cream mixes was more easily damaged.5 The analysis of nutritional components of probiotic-containing soft ice-cream mixesAccording to the national standard method to analyze the basic nutritional components of homemade soft ice-cream mixes samples, the results indicated that:water content of 65.67% ± 0.39%, the content of crude fat was 9.85g/100g ± 0.13g/100g, crude protein content was 4.50g/100g ± 0.28g/100g, the total sugar content is 16.58g/100g ± 0.29g/100g. Compare with sold ice-cream samples, homemade soft ice-cream mixes has the minimum water content and crude protein content. But the content of crude fat of homemade samples is still higher than some sold samples, although we have used alternatives. But fat content is a great influence on the quality of ice-cream taste, so it’s reasonable. Total sugar content is basically reasonable. Further analysis on the nutritional components of soft ice-cream mixes by using the method of atomic absorption spectrophotometer and HPLC, the results indicated that:soft ice-cream mixes contains some physiological activity mineral elements, such as Fe, Ca, Mg, Cu, and Zn. And the content of Fe was 8.23±0.1269 mg/L, Ca was 131.9±1.03 mg/L, Zn was 0.617±0.0125 mg/L, Mg was 17.46±0.263 mg/L, Cu was 1.336±0.0053 mg/L. Amino acid analysis showed that, the content of kinds of amino acids, total amino acids content, the essential and non-essential amino acids, conditionally essential amino acid, essential amino acids of children’s growth are higher than the other samples. Total amino acids content of soft ice-cream mixes samples was 1.513%, the essential amino acid content was high, and the essential amino acids accounted for 44.90% in total amino acids, the ratio of essential amino acid and nonessential amino was 81.48%, the first limiting amino acid of soft ice-cream mixes is valine, the second limiting amino acid is ISO-1-Leucine. |
PDF Full Text Request