Assessing the stability of rebaudioside A in UV light
A study published in the Journal of Food Science examines the degradation rate of rebaudioside A in water, phosphate buffer, and citrate buffer when exposed to ultraviolet (UV) light.
A study published in the Journal of Food Science examines the degradation rate of rebaudioside A in water, phosphate buffer, and citrate buffer when exposed to ultraviolet (UV) light. Rebaudioside A is a natural noncaloric high-potency sweetener extracted from the leaves of Stevia rebaudiana. With rebaudioside A use increasing in foods, understanding the factors affecting its stability is necessary.
The researchers evaluated the degradation rate constants of rebaudioside A in water, 0.1 M phosphate buffer, and 0.1 M citrate buffer at pH 3 and 7 as a function of UV light intensity (365 nm, 0 μW/cm2 for dark conditions, 27 μW/cm2 for low intensity, and 190 μW/cm2 for high intensity) at 32.5°C. They found that rebaudioside A stability was adversely affected by light exposure. The degradation rate constants increased significantly with increasing light intensity in all solutions.
Under dark conditions, rebaudioside A in phosphate buffers was more susceptible to breakdown than in water and citrate buffers at both pH levels. However, exposure to UV light resulted in rebaudioside A degradation occurring approximately 10 times faster in citrate than in phosphate buffers at both pH levels. The sensitivity of rebaudioside A to UV light was greater in citrate buffers than in water or phosphate buffers.
The researchers concluded that light exposure has an adverse effect on the stability of rebaudioside A. “Proper formulations, light-protective packaging, and cool storage conditions are strategies that will improve the stability of rebaudioside A in food products,” wrote the researchers.