Pires Arona, Gomes David, Noronha João, Díaz Olga, Cobos Angel, Pereira Carlos Dias
Escola Superior Agrária, Politécnico de Coimbra, Bencanta, 3045-601 Coimbra, Portugal.
Departamento de Química Analítica, Nutrición y Bromatología, Área Tecnología de Alimentos, Facultad de Ciencias, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
Foods. 2022 Dec 17;11(24):4091. doi: 10.3390/foods11244091.
Second cheese whey (SCW) is the by-product resulting from the manufacture of whey cheeses. In the present work, sheep (S) and goat (G) SCW concentrated by ultrafiltration (UF) were used in the production of ice creams. Concentrated liquid SCW samples with inulin added as a prebiotic were fermented with yoghurt, kefir and probiotic commercial cultures before being frozen in a horizontal frozen yoghurt freezer. The physicochemical, microbiological and sensory properties of the products were evaluated over 120 days of frozen storage. The products presented significant differences regarding these properties, specifically the higher total solids and protein contents of sheep's ice creams, which were higher compared to their goat ice cream counterparts. Sheep's ice creams also presented higher hardness and complex viscosity, which increased with storage. These ice creams also presented higher overrun and lower meltdown rates. The color parameters of the ice creams showed significant differences between formulations resulting from storage time. In all cases, sp. cell counts were higher than log 6 CFU/g at the first week of storage. In the case of sheep's ice creams these values were maintained or increased until the 30th day, but decreased until the 60th day. sp. counts surpassed log 7 CFU/g in all products, and these values were maintained until the end of storage, except in the case of G-Yoghurt and G-Kefir. Concerning the products containing probiotics, the sum of sp. and sp. counts was of the order log 8-9 CFU/g until the 60th day of storage, indicating that the probiotic characteristics of ice creams were maintained for at least 2 months. All products were well accepted by the consumer panel. Sheep's SCW ice creams were better rated regarding aroma, taste and texture. However, only the ranking test was able to differentiate preferences among formulations.
二次乳清(SCW)是乳清奶酪生产过程中产生的副产品。在本研究中,通过超滤(UF)浓缩的绵羊(S)和山羊(G)二次乳清被用于生产冰淇淋。添加菊粉作为益生元的浓缩液态SCW样品,在卧式冷冻酸奶冷冻机中冷冻之前,先用酸奶、开菲尔和商业益生菌培养物进行发酵。在120天的冷冻储存期内对产品的物理化学、微生物和感官特性进行评估。这些产品在这些特性方面存在显著差异,特别是绵羊冰淇淋的总固形物和蛋白质含量更高,比山羊冰淇淋同类产品更高。绵羊冰淇淋还表现出更高的硬度和复数粘度,且随着储存时间增加。这些冰淇淋还具有更高的膨胀率和更低的融化速率。冰淇淋的颜色参数因储存时间不同而在配方之间显示出显著差异。在所有情况下,储存第一周时,嗜热链球菌细胞计数均高于log 6 CFU/g。对于绵羊冰淇淋,这些值在第30天之前保持不变或增加,但在第60天之前下降。嗜热链球菌计数在所有产品中均超过log 7 CFU/g,除了G-酸奶和G-开菲尔产品外,这些值一直保持到储存结束。对于含有益生菌的产品,在储存第60天之前,嗜热链球菌和嗜酸乳杆菌计数之和约为log 8 - 9 CFU/g,这表明冰淇淋的益生菌特性至少维持了2个月。所有产品都受到消费者小组的好评。绵羊二次乳清冰淇淋在香气、味道和质地方面评分更高。然而,只有排序测试能够区分不同配方之间的偏好。