以蓮藕粉、葛鬱金粉製作優格對產品特性及感官品評之研究

優格(yogurt)含有益生菌，是一種營養豐富且對整體健康有益的食品，市面上優格產品常常使用添加劑以增加產品的濃稠度與避免沉澱。本研究使用台灣在地的蓮藕粉(lotus root powder, LRP)和葛鬱金粉(arrowroot powder, ARP)，分別以0.5%和1%比例添加至鮮奶，加熱至80°C維持30分鐘，以確保粉充分糊化。待冷卻至45°C後，加入菌種於45°C發酵7小時後，移至4°C冷藏16小時進行後發酵製成優格，再分析其製成率、pH值、色澤、水活性、堅實度和感官品評特性。結果顯示：本研究添加LRP和ARP製成優格明顯提升了製成率，也降低了優格的水活性。添加比例是影響製成率和水活性的主要因素，製成率LRP-1%處理組和ARP-1%處理組顯著較高(86.4%、87.0%)，兩者的水活性(0.958、0.962)也顯著較低(P<0.05)。pH值方面所有組別沒有顯著差異(P>0.05)，表示粉添加並未影響優格的發酵。色澤方面，對照組有顯著最高L*值 (92.24)及顯著最低b*值(6.62)，a*值則是以ARP-0.5%處理組(-3.37)和ARP-1%處理組(-3.70)顯著最低(P<0.05)。在堅實度方面LRP-1%最高(171.22 g)，添加比例是影響堅實度的主要因素。感官品評結果亦顯示粉添加提高了產品的喜好度，且以ARP-1%處理組喜好度最高。整體來說，LRP和ARP的添加提高了製成率、保水力和堅實度，並且降低了水活性，換句話說，添加LRP和ARP天然澱粉能使優格產品降低生產損耗，提升口感並穩定產品狀態。

關鍵字

蓮藕粉；葛鬱金粉；優格；糊化

並列摘要

Yogurt contains probiotics and is a nutritious food that is beneficial to overall health. Commercial yogurt products often add food additives to increase the product's thickness and stability. This study used local Taiwanese lotus root powder (LRP) and arrowroot powder (ARP), which were added to fresh milk at 0.5% and 1% concentrations, then heated to 80°C and maintained for 30 minutes to ensure full gelatinization. After cooling to 45°C, the starter was added and fermented at 45°C for 7 hours, and then refrigerated at 4°C for 16 hours to preprare yogurts. Yogurt production was performed for all analyses including yield, pH, color, water activity, firmness, and sensory characteristics. The results showed that yogurts made with LRP and ARP significantly improved the yield, and their water activity was lower than the control group. The powder concentration was the main factor affecting yield and water activity. both the LRP-1% and ARP-1% groups showed significantly higher yields (86.4%, 87.0%), and lower water activity (0.958, 0.962) (P<0.05). In terms of pH, no significant differences were observed among all groups (P>0.05), indicating that the addition of powders had no influence in yogurt fermentation. In color, the control group showed the significantly highest in L* value (92.24) and the lowest b* value (6.62), while the significantly lowest a* value was obtained in the ARP-0.5% group (-3.37) and ARP-1% group (-3.70) (P<0.05). In terms of firmness, the LRP-1% group showed the highest value (171.22 g), indicating that powder concentration is the main factor affecting the texture of yogurt. Sensory evaluation also showed that the addition of powders increased sensory scores and the ARP-1% treatment group had the highest panelist’s preference. Overall, the addition of LRP and ARP increased yield, water retention, and firmness, while reducing water activity. In other words, the addition of native powders (LRP and ARP) can reduce production loss, improve taste, and improve the stability of yogurt products.