Storage of refrigerated raw goat milk affecting the quality of whole milk powder

Abstract

The aim of this study was to evaluate the influence of the growth of lipolytic bacteria in raw goat milk stored under refrigeration for different periods on quality parameters of goat milk powder during its shelf life. Fresh goat milk (100L) was collected after milking, divided into 3 identical fractions, and stored at 4°C for 1, 3, and 5d. On d 1, 3, and 5, one sample (1L) was collected and used for microbiological and chemical analysis, and the remaining fraction (almost 30L) was spray dried and stored at 25°C. Milk powder was submitted to microbiological, chemical, and sensory analysis immediately after production, and on d 60, 120, and 180. Lipolytic psychrotrophic counts and total free fatty acid content did not increase in raw milk during storage. However, peroxide value, caprylic and capric acid concentrations, and total free fatty acid content of milk powder increased during 180d of storage, with higher levels found in milk powder manufactured with raw milk stored for 5d. Capric odor and rancid flavors increased in milk powder during storage, regardless the of storage of raw milk for 1, 3, or 5d. Heat treatments used during powder processing destroyed lipolytic psychrotrophic bacteria, but did not prevent lipolysis in milk powder. Results of this trial indicate that the storage of raw goat milk at 4°C should not exceed 3d to preserve the quality of goat milk powder during its shelf life of 180d.

Characterization of the indigenous microflora in raw and pasteurized buffalo milk during storage at refrigeration temperature by high-throughput sequencing

“…In addition, pasteurization is used to reduce the microbial load of milk, but the lysis of psychrotrophic bacteria may lead to the release of heat resistant proteolytic and lipolytic enzymes that could affect the shelf life of milk and dairy products such as cheeses and milk powders. A previous study showed that heat-resistant proteolytic enzymes from psychrotrophic bacteria could result in the degradation of cheese caseins, resulting in a reduced cheese yield (Mankai et al, 2012); whereas another report showed that raw goat milk should not be stored for more than 3 d at 4°C after heat treatment or the presence of lipolytic enzymes will reduce the quality of milk powder, which typically has a shelf-life of 180 d (Fonseca et al, 2013). In addition, gram-positive spore-forming bacteria are also known to contribute to milk spoilage, as they may survive heat treatments and become a dominant population within the microflora of pasteurized milk (Ranieri et al, 2009).…”

Cupuassu (Theobroma grandiflorum) pulp, probiotic, and prebiotic: Influence on color, apparent viscosity, and texture of goat milk yogurts

“…When compared with cow milk, goat milk has the following characteristics: (1) less soluble and more insoluble contents of volatile FA, (2) a higher percentage of medium-and short-chain FA, (3) casein micelle with a lower percentage of α S1 -casein fraction, (4) smaller size of casein micelle, and (5) more calcium and inorganic phosphorus . Furthermore, the importance of goat milk as a functional food is due to its high digestibility and nutritional value, as well as its therapeutic and dietary characteristics (Park et al, 2007;Fonseca et al, 2013). For these reasons, it is an excellent substitute for cow milk in the nutrition of children and elderly persons Kapila et al, 2013).…”

Parâmetros de qualidade do leite de cabra armazenado sob frio

“…Também Fonseca et al (2013) não observaram efeito do Tabela 1. Percentual médio dos componentes do leite caprino em amostras analisadas após ordenha (fresca) e após armazenamento por oito dias sob refrigeração (6ºC) e congelamento (-18ºC).…”