Elevated temperature extraction of β-carotene from freeze-dried carrot powder into sunflower oil: Extraction kinetics and thermal stability

beta-Carotene, a precursor of vitamin A, can alleviate the deficiency of this vitamin prevalent worldwide. Earlier research studies have addressed the extraction of beta-carotene at relatively low temperatures (up to 70 degrees C) due to its perceived instability at higher temperatures, as a result of which extraction rates recorded are relatively low. This study models the net rate of beta-carotene extraction by considering both extraction and degradation kinetics. The model developed, which accounts for degradation occurring in solid and extract phases, has been experimentally validated for the extraction of beta-carotene from freeze-dried carrot powder into sunflower oil over a range of temperatures 90-150 degrees C. This study also gives insights into the application of sunflower oil as a carrier for beta-carotene during cooking and food processing, by monitoring and modeling the thermal degradation and isomerization of beta-carotene at temperatures up to 220 degrees C. The modeling of extraction kinetics shows that it is possible to achieve viable extraction rates by employing temperatures in the range (90-150 degrees C) for relatively short times (<5 min). The degradation kinetics shows that almost 75% of the beta-carotene can survive heating at 180 degrees C for 10 min-indicating the possibility of using beta-carotene enriched edible oils for frying. This study also reports on the formation of three isomers of beta-carotene identified using HPLC: trans-, 9-cis, and 13-cis. The reaction network model developed in this study was able to account for the transient variation of the concentration of all three isomers. PRACTICAL APPLICATION: beta-Carotene is a precursor of vitamin A and its consumption can potentially alleviate the deficiency of this vitamin prevalent worldwide. This study validates a model for the extraction of beta-carotene in sunflower oil, which takes into account extraction as well as degradation occurring during extraction, so that a rational method is available for the design of efficient extractors for this purpose. This paper also establishes the thermal stability of beta-carotene under frying conditions by quantifying its thermal degradation as well as isomerization. Practical Application: beta-Carotene is a precursor of vitamin A and its consumption can potentially alleviate the deficiency of this vitamin prevalent worldwide. This study validates a model for the extraction of beta-carotene in sunflower oil, which takes into account extraction as well as degradation occurring during extraction, so that a rational method is available for the design of efficient extractors for this purpose. This paper also establishes the thermal stability of beta-carotene under frying conditions by quantifying its thermal degradation as well as isomerization.