Potential Application of Athermal Approaches in Processing Apple Juice: A Perspective From Vietnam

In recent years, the application of athermal processing methods has gained increasing attention as a promising approach in preserving temperature-sensitive health-beneficial phytochemicals in food and beverage products, especially those containing naturally derived ingredients. This study focused on exploring the impacts of emerging athermal juice processing methods, including forward osmosis concentration and ultrasonic-assisted sterilization, on the phenolic and flavonoid content of apple juice products, while also employing the Box-Behnken experimental design approach to optimize key parameters of these processing methods for the purpose of maximizing phytochemical retention. Overall, under optimized conditions, these athermal processing methods were capable of preserving over 84% of the total phenolic and flavonoid content of apple juice (388.61 ± 7.82 mgGAE/L and 288.03 ± 8.22 mgQE/L, respectively, compared to 423.65 ± 5.48 mgGAE/L and 339.54 ± 3.03 mgQE/L for untreated apple juice samples). Noticeably, these values were markedly higher than most pre-packaged apple juice products currently available in Vietnam; other than one single brand, the highest values of total phenolic and flavonoid content recorded for PP products were only 346.25 ± 1.59 mgGAE/L and 203.29 ± 0.59 mgQE/L, respectively. This result highlighted the need to modernize manufacturing facilities in order to better satisfy the expectations of increasingly health-conscious consumers. PRACTICAL APPLICATIONS: Apple juice concentrates are the main ingredient for most reconstituted clear apple juice products. This study demonstrated the applicability of emerging athermal processing methods in the manufacturing of apple juice concentrates that are both shelf-stable and nutritious, retaining the majority of phytochemicals existing in natural apple juice. Through comparing nutritious contents with commercial apple juice products currently available in the Vietnam market, especially products from domestic brands, it was evidenced that such an athermal approach could be employed by local manufacturers in order to improve the quality of their products.