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• Effects of Frozen Storage on the Physical Properties and Sensory Acceptability of Goat’s Milk Yoghurt

  Nguyen Duc Doan, Vicky Ann Solah

  Received: Feb 14, 2019 / Published: Jun 05, 2020

   Abstract PDF

  The effects of frozen storage of goat’s milk on the physicochemical, physical properties, and sensory attributes of goat’s milk yoghurts were evaluated. Four yoghurts were made from goat’s milk stored at 4℃ overnight, and at -6, -20, or -35℃ for 1 month. Goat’s milk yoghurts were stored at 6℃ for 21 days. Protein and lipid contents in all the yoghurts were insignificantly different, however, the total solids content, including the added sugar in the yoghurts made from frozen goat’s milk, significantly increased in comparison with that in the yoghurt made from chilling goat’s milk. The water holding capacity (WHC) and viscosity for all the yoghurts at any period of cold storage were statistically different. No significant differences in pH or titratable acidity for all the yoghurts were observed after 1 day of cold storage; however, these physicochemical properties for the yoghurts after 7 days of storage were significantly different. All the yoghurts after 21 days of storage received similar scores for appearance and texture, but significantly different scores for color, odor, flavor, and overall acceptability. 

• Genetic Divergence of Cultivated Rice Varieties in North Vietnam for Grain Quality Traits Using D2 Cluster Analysis

  Nguyen Ba Thang

  Received: Oct 21, 2021 / Published: Jun 27, 2022

   Abstract PDF

  The study was carried out with twenty-four genotypes of rice during the Spring season, 2020 in Hanoi, Vietnam in order to exploit the attributes and divergence of quality properties from existing rice cultivars in North Vietnam. The rice genotypes were characterized based on ten quality parameters of milling, physical appearance and physiochemical characters using Mahalanobis D2 statistic. D2 analysis allocated the 24 genotypes into eight clusters, of which cluster I was the largest with 12 genotypes. The clustering showed the random distribution of genotypes into different clusters indicating that the origin and release duration were not related to the genetic diversity of grain quality. Among different traits, amylose content, length/width ratio and gel consistency were identified as topmost contributors in total divergence. Cluster I possessed a maximum intra-cluster value of 296.34 and the maximum inter-cluster distance was recorded between cluster IV and VI (2247.39) succeeded by cluster I and VI (2245.94) designing the members presented in these clusters can be exploited as potential donors in a breeding program to result good physicochemical quality traits in rice.

• Evaluation of the Physicochemical Properties and Sensory Attributes of Yoghurt Made from Mixtures of Goat’s and Cow’s Milks

  Nguyen Duc Doan

  Received: Mar 06, 2019 / Published: Dec 24, 2019

   Abstract PDF

  The objective of the study was to evaluate the effect of cow’s milk added to goat’s milk on physicochemical properties and sensory attributes of yoghurt. Yoghurts prepared from five different proportions of cow’s milk and goat’s milk were stored at 4-6ºC for 1, 7, and 14 days and then evaluated for their physicochemical (total solids, protein, pH, and acidity) and physical properties (viscosity and water holding capacity), and sensory characteristics (acceptability). The total solids of the evaluated yoghurts significantly increased, but the protein content decreased when the amount of cow’s milk increased in the mixtures of milk. The results showed that the pH value of the yoghurt made from only goat’s milk was higher, while the titratable acidity was lower than those of the yoghurts made from the mixtures of goat’s and cow’s milks. The yoghurt obtained from the mixture of milks containing 80% goat’s milk and 20% cow’s milk exhibited the highest viscosity and water holding capacity among the evaluated yoghurts. All the yoghurts received similar scores for color, odor, and texture after all periods of storage, while the highest score in terms of flavor was received for the yoghurt made from the mixture of milks containing 60% goat’s milk and 40% cow’s milk. Addition of cow’s milk to goat’s milk was shown to significantly contribute to the viscosity, water holding capacity, and flavor of the resulting yoghurts.