Yoghurt production with ginger juice: Determination of organic acids and volatile compounds

In this study, it was examined to add freshly squeezed ginger juice to the milk used in yoghurt production during heat treatment before fermentation. Yoghurts with honey as well as yogurts with ginger were also produced. Ginger juice was added in the ratios of 0%, 0.5% and 1.5% and ginger juice-honey mixes were added in the ratios of 0%, 0.5%-0.5% and 1.5%-1.5% to the milk. During storage chemical (dry matter, pH, titratable acidity, fat, protein, carbohydrate, ash), biochemical (volatile compounds, organic acids), physical (color, viscosity and serum separation) analyses and sensory evaluations are conducted in yoghurts. Volatile compound analysis was made by solid phase microextraction technique with gas chromatography-mass spectrophotmetry; organic acid analysis was determined by high performance liquid chromatography. While lactose decreases during storage; glucose and galactose amounts showed an increasing trend. Fructose was found in yoghurts containing 0.5% and 1.5% honey at levels of 1992 mg / kg and 5976 mg / kg, respectively. Lactic acid was the most abundant organic acid found in yoghurts, followed by citric, butyric, formic and acetic acids. Yogurts containing ginger juice has the highest concentration of orotic acid compared to the others; succinic acid was determined in the highest level in yoghurts with ginger juice+ honey and acetic acid in control yoghurts. The number of volatile compounds in yoghurts increased with the increase in ginger juice ratio. Yoghurts with ginger contained a high proportion of terpene components compared to the control yoghurt. The main terpenes were β-sesqupallendyren, sabinene and zingiberene. In terms of physical properties, the least serum separation at the end of storage was observed in control yogurt. While the control yogurt had the highest general acceptability score in terms of sensory evaluations; yogurts with ginger juice and yoghurts with ginger juice + honey had a similar acceptability score. However ginger juice + honey added yoghurts showed better sensory storage stability compared to other yogurts. As a result, it was determined that ginger juice alone or ginger juice + honey can be used in the production of set yogurt up to 1.5% in terms of both the abundance of terpene compounds and sensory storage stability.