Characteristics and fatty acid composition of milk fat from Saudi Aradi goat

Abstract

SUMMARY:Goat milk is the second most prevalent edible milk in Saudi Arabia and is one of the most prominently produced milks in the world. Few studies have focused on the physicochemical properties of goat milk fat (GMF). Samples of Saudi Aradi goat milk were obtained during the spring dairy season to determine the physicochemical characteristics and fatty acid composition of the GMF. The physicochemical properties of Saudi Aradi GMF were as follows: iodine value, 23.2 g of I 2 ·100 g −1 of fat; saponification value, 213.2 mg KOH·g −1 of fat; refractive index (25 °C), 1.4583; unsaponifiable matter, 0.54%; acidity, 0.52%; and peroxide value, 2.07 meq O 2 ·kg −1 of fat. α-Tocopherol was the major tocol (70.9%), followed by β-tocopherol (22.02%). GMF had significant contents of polyunsaturated fatty acid (FA) (6.16%), conjugated linolenic acid (0.36%), saturated FA (67.04%) and branched FA (1.98%). The thermal profiles of the Saudi Aradi GMF samples were examined using a thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Saudi Aradi GMF showed some absorbance in the UV-C range. This study demonstrated that the milk fat from the Saudi goat has physically and chemically favorable properties, as well as good nutritional properties, as a source of essential fatty acids and fat-soluble vitamin E. KEYWORDS: Fatty acids; Goat milk fat; Physicochemical properties; Thermal analysisRESUMEN: Características y composición en ácidos grasos de la grasa láctea de cabras de Arabia Saudí. La leche de cabra es la segunda leche comestible predominante en Arabia Saudí y es una de las leches de mayor producción en el mundo. Pocos estudios se han centrado en las propiedades físico-químicas de la grasa de leche de cabra (GLC). Muestras de leche de cabra Arabia Saudí fueron obtenidas durante la temporada de mayor producción lechera, durante la primavera, y se determinaron sus características físico-químicas y la composición de ácidos grasos de la GLC. Las propiedades fisicoquímicas determinadas de la GLC de Arabia Aradi fueron las siguientes: índice de yodo, 23,2 g de I 2 ·100 g −1 de grasa; índice de saponificación: 213,2 mg de KOH·g −1 de grasa; índice de refracción a 25 °C: 1.4583; insaponificable: 0,54%; acidez: 0,52%; y el índice de peróxidos, 2,07 meq O 2 ·kg −1 de grasa. α-tocoferol fue el principal tocol (70,9%), seguido de β-tocoferol (22,02%). La GLC tiene un contenido significativo de ácidos grasos poliinsaturados (FA) (6,16%), ácido linoleico conjugado (0,36%), ácidos grasos saturados (67,04%) y ácidos grasos ramificados (1,98%). Los perfiles térmicos de las muestras de GLC de Arabia Aradi fueron examinados utilizando análisis térmico gravimétrico (ATG) y calorimetría diferencial de barrido (CDB). La GLC de Arabia Aradi mostró cierta absorbancia en el rango UV-C. Este estudio demostró que la grasa de la leche de la cabra de Arabia tiene propiedades física y químicamente favorables, así como buenas propiedades nutricionales, como fuente de ácidos grasos esenciales y vitamina E liposoluble.

Thermogravimetric characterization of dark and milk chocolates at different processing stages

“…The profiles of the TG and DTG curves in oxygen showed five stages of decomposition of milk fat, with maximum temperature at 95, 296, 340, 414, and 511°C. Sbihi et al [31] obtained similar results by studying goat milk fat under dry air atmosphere. Milk fat due to its structure is polymorphic fat [32].…”

Characterization of thermal properties of goat milk fat and goat milk chocolate by using DSC, PDSC and TGA methods

“…Sbihi et al [21] investigated goat milk fat. They observed that during DSC analysis, melting curve exhibited two melting peaks at 15.4°C and 38.7°C, respectively.…”

“…In contrast to a nitrogen atmosphere, a TG diagram performed under oxygen atmosphere was characterized by four transitions; therefore, a DTG curve showed four stages of goat milk fat decomposition at maximum temperature peaks: 278.13; 409.77; 417.99; and 502.12°C. Sbihi et al [21] investigated goat milk fat by using TGA/DTG in a dry air atmosphere. The characteristic of the TGA/DTG diagrams showed three stages of decomposition for goat milk fat, with a maximum temperature at 316.5, 440 and at 541.3°C.…”

“…The activation energy for cocoa butter at isothermal conditions (160°C, oxygen atmosphere) is equal to 120.5 kJ mol -1 . Sbihi et al [21] investigated goat milk fat. The fatty acids composition influenced on thermal stability of goat milk fat.…”

Multivariate analysis of seasonal variation in the composition and thermal properties of butterfat with an emphasis on authenticity assessment

“…These methods include gas chromatography to assay fatty acids (Molkentin and Precht, 1987;Glaeser, 2002) and triacylglycerols, which are presently determined according to the Official method (EC Regulation No. 273/2008), liquid chromatography (NogalaKałucka et al, 2008;Derewiaka et al, 2011), near infrared spectroscopy (Heussen et al, 2007), and differential scanning calorimetry, which is commonly used in studies of milk fat from various animals (Sbihi et al, 2015;Tomaszewska-Gras, 2016b). Authenticity assessment of butter is still a big challenge for analytics.…”