The influence of milk quality and composition on goat milk suitability for cheese production

The goat milk production sector is growing in Latvia, therefore detailed studies are required to examine goat milk suitability for cheese production. There is still not enough information about the chemical composition and quality of goat milk, and its connection with milk renneting properties. The objective of this study was to analyse the impact of milk composition and quality on goat milk renneting properties. Fat, protein, lactose, urea content, somatic cell count and freezing point were measured by infrared spectroscopy. The curd firmness was analysed by Texture Analyser TA.HD.plus (Stable Micro Systems, UK). In total, 34 samples, including bulk milk samples (n = 3) were analysed. The analysed breeds included the Latvian Native (n = 9), Saanen (n = 14) and milking crosses (closer to Anglo Nubian) (n = 8). The samples were arranged according to the lactation, somatic cell count and breeds. Obtained fat content varied from 1.72 to 4.67%, and the protein content – from 2.93 to 4.57% in individual goat milk samples. The highest fat to protein ratio was established in the Saanen breed goat milk (0.96), but the lowest – in milking crosses’ milk (0.80). The highest somatic cell count was determined in the second lactation goat milk (1421 thous mL-1 ) and in milking crosses’ goat milk (1027 thous mL-1 ). The somatic cell count influences curd firmness in cheese, and the highest fat to protein ratio was established in the first group samples with lower somatic cell count

Acceptance of low-sugar yoghurt among Latvian teenagers

Over a thousand year history, yoghurt has become one of a widely consumed product in the world. Its reputation as a healthy food has been undermined recently by concerns over the high sugar content. The majority of consumers expects and prefers yoghurts to be sweet. However, governments across Europe are calling for significant cuts in the amount of added sugar used in yoghurt production. The aim of the study was to evaluate the acceptance of low-sugar yoghurt produced by different commercial β-galactosidases by teenagers. Standardised milk with fat content 2.0% (SC Tukuma piens) was pasteurized at 95 ± 1 °C 5 min, cooled down till 43 ± 1 °C and fermented with β-galactosidase and starter YC-X11 (Chr. Hansen, Denmark) and fermented till pH 4.50 ± 0.20. Different commercial β-galactosidases: Nola™ Fit 5500, Ha-Lactase 5200 (Chr. Hansen, Denmark), GODO-YNL2 (Danisco, Denmark) and BrennZyme (Brenntag PolskaSp, Poland) were used. Fermented samples were gently mixed and cooled down till 6 ± 1 °C and 5% (w/w) of sugar was added to each sample. Sensory evaluation of the yoghurt’s samples was performed by teenagers (14–18 years, n = 50) at Aizputes Secondary School (Latvia). Lactose and monosaccharides concentration prior to sugar addition was detected by HPLC (Shimadzu LC 20 Prominence, Japan). The lactose hydrolysis into glucose and galactose by the use of β-galactosidase helps to increase sweetness through an occurrence of natural sugars in milk. During sensory evaluation, teenagers admitted the yoghurt with reduced sugar as sweet, significantly sweeter (P < 0.05) was yoghurt sample with Nola™ Fit 5500. The results demonstrated that it is possible to reduce sugar in yoghurt production and to gain consumer acceptance through the occurrence of glucose and galactose, but it is problematic to offer lactose-free or reduced lactose products to consumers without lactose intolerance