應用序列二次規劃法開發益生菌乳錠

Abstract

本研究擬開發酸凝酪及克弗爾兩種不同風味含有活菌的乳錠，並評估保護劑添加對乳錠原料中菌元凍乾後活性之影響。保護劑添加之最佳濃度及比例，是藉由反應曲面法設計（RSM）建立最佳方程式，再利用序列二次規劃法（SQP）獲得。酸凝酪乳錠製造方法是將脫脂乳添加益菌質後，再接種酸凝酪菌元(Lactobacillus bulgaricus, Streptococcus thermophilus) 及益生菌 （L. paracasei, Bifidobacterium longum,)，於37℃發酵12小時，混入抗凍保護劑，最後將樣品凍乾、壓錠製成風味獨特之益生菌酸凝酪乳錠。最佳化結果推薦，添加 6.98％半乳糖、7％蔗糖、8％脫脂乳粉為抗凍保護劑時，可得最佳的凍乾菌數存活率。在克弗爾酸凝酪製造方面，將脫脂乳添加5％的克弗爾粒，於20℃發酵24小時，再進行乾燥、打錠。最適化結果顯示，添加4.53％的半乳糖、7％蔗糖及5.03％的脫脂乳粉，可以得到最好的乳酸菌存活率，兩個產品的驗證實驗證實乳酸菌試驗結果與預測值間沒有顯著差異（P>0.05）。儲存結果顯示室溫下儲存6個星期，益生菌含量仍有105-107CFU/g；官能評估之結果發現雖然酸凝酪乳錠及克弗爾乳錠在外觀及質地上並無顯著的差異，而風味方面，克弗爾乳錠則有較低的評分。

A number of novel fermented dairy products are being developed and marketed under the concept of probiotic products, but few of probiotics were associated with confectionary goods. Thus, the objective of this research was to develop two probiotic candies (yogurt flavor and kefir flavor) by freeze drying and evaluate the effect of lyoprotectants on viability of probiotics. The proportion of lyoprotectants (galactose, skim milk power and sucrose) was optimized using response surface methodology (RSM) to first construct a surface model, with sequential quadratic programming (SQP) subsequently adopted to optimize the model. The endpoint was to increase the varieties of probiotic products and enhance their market values. For manufacturing the yogurt flavor candy, skim milk was mixed with prebiotics and inoculated with yogurt cultures (Lactobacillus bulgaricus, Streptococcus thermophilus) and probiotics (L. paracasei, Bifidobacterium longum). After fermentation at 37℃ for 12 hours, the fermented samples were mixed with lyoprotectants, dehydrated by freeze drying and pressed to form tablets. Optimization results indicated that combination of 6.89% galactose, 7% sucrose and 8% skim milk powder would produce the highest survival in terms of probiotic count. For manufacturing the kefir candy, the processing steps were similar to yogurt samples except for the preparation of the kefir culture. To prepare the culture, skim milk was mixed with 5% kefir grains and incubated at 20℃ for 24 hours to produce the kefir culture. Results indicated that combination of 4.53% galactose, 7% sucrose and 5.03% skim milk powder would generate the highest survival of lactic acid bacterial count. The verification experiments yielded results close to the predicted values, with no significant difference (P>0.05) for both samples. The storage results demonstrated that these probiotic counts remained above 105-107 CFU/g stored for six weeks under room temperature. Sensory evaluation results revealed no significant difference between the yogurt and kefir samples in appearance and texture. However, the kefir flavor candy was sour and had the lower score in aroma.