تاثير غلظت‌هاي مختلف نمك بر ويژگي‌هاي فيزيكو‌شيميايي و حسي پنير سفيد پروبيوتيك تهيه شده به روش فراپالايش

The Effect of Different Salt Concentrations on the Physicochemical and Sensory Properties of Probiotic White Cheese Prepared by Ultrafiltration Method

با توجه به تقاضاي مصرف‌كنندگان براي توليد مواد غذايي فراسودمند و سلامت بخش، در اين تحقيق توليد پنير پروبيوتيك با محتواي نمك پايين مورد مطالعه قرار گرفت. به اين منظور با استفاده از روش آماري سطح پاسخ و طرح مركب مركزي پنير با سطوح متفاوت نمك (2، 3 و 4 درصد) و دو نوع سويه‌ پروبيوتيك (لاكتوباسيلوس اسيدوفيلوس و بيفيدوباكتريوم لاكتيس) تهيه و طي مدت نگهداري 60 روز مورد ارزيابي قرار گرفت. مدل‌هاي برازش شده جهت پيشگويي متغير‌هاي پاسخ انتخاب شده شامل خصوصيات شيميايي، ويژگي‌هاي حسي، زنده‌ماني باكتري‌هاي پروبيوتيك و خصوصيات مكانيكي بافت ضريب تبيين بالايي را نشان داد. نتايج آناليز واريانس نشان داد كه تغيير غلظت نمك اثر معني‌داري بر ويژگي‌هاي فيزيكي‌شيميايي، پارامترهاي بافتي و پذيرش كلي داشت (05/0>p)، در حالي‌كه بر قابليت زنده‌ماني باكتري‌هاي پروبيوتيك بي‌تاثير بود 05/0

Reducing of salt content in cheese production is an important challenge for the dairy industry. Based on consumer demand for functional and healthy food, in this study, the feasibility of salt reduction in ultrafiltered white probiotic cheese was studied. For this purpose, white probiotic cheese was prepared with different levels of salt (2, 3 and 4%) with two probiotic strains (Lactobacillus acidophilus and Bifidobacteriumlactis) using response surface methodology and central composite design, and evaluated during 60 days storage time. Fitted models showed a high correlation coefficient to predict selected response variables including chemical and sensory characteristics, survival of probiotic bacteria and textural properties in UF-cheese. ANOVA results showed that change in salt concentration had a significant effect on physicochemical characteristics, texture parameters and overall acceptance (P<0.05), while the survival of probiotic bacteria was unaffected. According to the obtained results, by increasing the salt concentration in cheese the syneresis and dry matter, as well as the hardness of the samples increased, while the acidity and cohesiveness were decreased. Viability of probiotic bacteria was affected by storage time, so that the number of Lactobacillus acidophilus in low salt probiotic cheese and at the end of storage period was more than Bifidobacterium lactis. Lowering the salt content of probiotic cheese led to a lower sensory acceptability. Optimum conditions to produce low salt probiotic cheese through Bifidobacterium lactis and Lactobacillus acidophilus were obtained 2.61% salt ( 18 days storage) and 2.49% salt (60 days storage), respectively.