| Abstract: | 稻米(Oryza sativa)為人類的主要糧食之一，臺農71號白米為霧峰地區著名的香米；黃豆(Glycine max)為重要的植物性蛋白來源，其中米富含甲硫胺酸和胱胺酸但缺乏離胺酸；黃豆富含離胺酸，但缺乏含硫胺基酸，因此本實驗以臺農71號白米與黃豆粉為原料，利用蛋白質的互補作用研發營養價值較高的冰淇淋，探討不同因子對冰淇淋理化性質及感官評估的影響，並將加工最適條件的冰淇淋進行12週的儲存性試驗。理化性質的項目包括:固形物含量、水含量、空氣膨脹率、黏度、乳化安定性、融化率、色澤分析、衛生指標菌及顯微鏡觀察；感官評估的項目包含:外觀、顏色、氣味、口感、風味及總評。 實驗結果顯示在主原料的影響方面，100%香米冰淇淋有最高的黏度、L值及白度，其值為6050 cp、83.83及78.01；100%黃豆冰淇淋有最高的乳化安定性及a值，其值為74.66%及4.71。動物性鮮奶油的含量方面，添加40%動物性鮮奶油之冰淇淋有最高的固形物、空氣膨脹率、L值及白度，其值為68.08%、33.94%、70.77及63.46，不含動物性鮮奶油之冰淇淋有最高的水含量、黏度及乳化安定性，其值為39.08%、2750 cp及 66.53%，感官評估總評項目中添加20%鮮奶油冰淇淋具有最高的得分，其值為6.17分。植物性鮮奶油含量方面，40%植物性鮮奶油之冰淇淋有最高的固形物、空氣膨脹率、L值及白度增加，其值為65.86%、33.94%、78.30及68.13。在儲藏性試驗方面，儲存第12週有最高的固形物含量其值為68.49%，有最低的水含量其值為31.51%，總生菌數及大腸桿菌群隨著儲藏時間的增加有降低的趨勢，各週總生菌數及大腸桿菌群皆在20,800 CFU/ml以下及6.1 MPN/ml以下，大腸桿菌檢測結果也呈陰性，符合我國衛福部冰類微生物衛生標準。上述結果顯示臺農71號白米與黃豆粉的比例、動物性鮮奶油含量及植物性鮮奶油含量對冰淇淋的品質都有顯著的影響；米與黃豆粉1:3、添加20%動物性鮮奶油或20%植物性鮮奶油的冰淇淋在乳化安定性及空氣膨脹率有適中的表現，且有最佳的適口性。
Tanung No. 71 is a polished rice with pleasant fragrance from Wufeng area, Taichung; soybean is an important source of plant protein. While rice protein is rich in methionine and cysteine, but lack of lysine, soybean protein is rich in lysine but lack of methionine and cysteine. The present study used Tainung No. 71 and soybean powder in different proportions as main ingredient to develop a high nutrition value ice cream, with complement in protein, as well as sensory improvements. The effects of change in ratio of rice/soybean powder main ingredient on physiochemical properties of ice cream, including solid content, water content, overrun, viscosity, fat stabilization, melting rate, color analysis, bacteria and microscope observation, and also sensory evaluations were carried out to obtain an optimal formulation. For sensory evaluation, appearance, color, odour, taste, flavor, and overall scores were obtained. Eventually, a 1:3 rice to soybean powder provided an optimal main ingredient ratio, and up to 40% of whipping cream was added to study the physiochemical properties and sensory evaluation of ice cream. A formulation using 20% animal or plant based whipping cream was found to provide the most palatable ice cream. Results of a 12 weeks, -20?C storage period to monitor the stability in physiochemical properties, sensory items and microbial level of this ice cream showed limited variations and the microbial tests met the hygiene standards of Ministry of Health and Welfare in Taiwan. |
