Factors affecting ascorbic acid content and keeping quality of Shammi goat milk

Abstract

The effect of pasteurization (65 °C for 5 s; 65 °C for 30 min; 72 °C for 15 s; or 85 °C for 5 s); preheating (70 °C or 75 °C); forewarming (90 °C or 95 °C); boiling (100 °C or 100 °C for 15 min), shaking (15 min); freezing (−20 °C); heavy metals (Cu, Fe, Ni and Cr); sunlight and subsequent storage on the ascorbic acid of Shammi goat milk were investigated. In addition, the influence of garlic and onion extracts at levels of 1%, 2%, 3% and 4% on the keeping quality of these milk samples was investigated. The ascorbic acid content in treated milk samples was reduced more rapidly as the time of exposure, the temperature and storage period increased. It was also shown that different types of container afforded different degrees of protection for ascorbic acid. Treatment of milk samples with garlic extract at a level of 1–4% or onion extract at a level of 1–2% can extend the keeping quality of milk samples for up to 4 days and treatment with onion extract at a level of 3–4% for up to 5 days. It can be concluded that exposure of Shammi goat milk to sunlight, heat treatments, heavy metals, shaking and storage period accelerated the loss of its ascorbic acid ( P < 0.01).