Influence of simulated food and oral processing on carotenoid and chlorophyll in vitro bioaccessibility among six spinach genotypes.

Increasing the density of micronutrients and phytochemicals in vegetable foods through plant breeding and processing is of value for consumers. However, the extent to which interactions between genetics and processing (G × P) can be leveraged for green leafy vegetables to improve the delivery of such compounds is unknown. Using spinach as a model, a three-phase in vitro digestion method with and without simulated oral processing (mastication) and coupling to a Caco-2 human intestinal cell culture model was used to determine whether bioaccessibility and intestinal uptake of carotenoids and chlorophylls can be modified from six spinach genotypes, fresh or processed as blanched, sterilized, and juiced products. Carotenoid and chlorophyll bioaccessibility varied significantly with the genotype (p < 0.001) and processing treatment (p < 0.001), with processing having a more profound influence on the bioaccessibility, decreasing micellarization of phytochemicals from juiced (25.8-29.3%), to fresh (19.5-27.9%), to blanched (14.9-20.5%), and sterilized spinach (10.4-13.0%). Oral mastication had a significant influence on the carotenoid bioaccessible content of sterilized spinach (0.3-0.5 µmoles per g DW) as compared to fresh spinach (0.1-0.3 µmoles per g DW), most likely due to the additive effect of thermal processing and mastication on facilitating digestive breakdown of the spinach matrix. Caco-2 accumulation of carotenoid and chlorophyll was modestly but significantly (<0.001) lower in fresh spinach (2.4%) compared to other treatment samples (3.7-4.8%). These results suggest that the genotype, processing treatment, and genotype × processing (G × P) interaction may affect carotenoid and chlorophyll bioaccessibility in spinach and that food processing remains a dominant factor in modulating the bioavailability of these phytochemicals.

Development of a genetic framework to improve the efficiency of bioactive delivery from blueberry.

In the present study, we applied a novel high-throughput in vitro gastrointestinal digestion model to phenotype bioaccessibility of phenolics in a diverse germplasm collection representing cultivated highbush blueberries. Results revealed significant (P < 0.05) differences between accessions, years, and accession by year interaction for relative and absolute bioaccessibility of flavonoids and phenolic acids. Broad sense heritability estimates revealed low to moderate inheritances of relative and absolute bioaccessibility, suggesting that besides environmental variables, genetics factors could control bioaccessibility of phenolics. Acylated anthocyanins had significantly higher relative bioaccessibility than non-acylated anthocyanins. Correlation analysis indicated that relative bioaccessibility did not show significant association with fruit quality or raw concentration of metabolites. The study also identified accessions that have high relative and absolute bioaccessibility values. Overall, combining the bioaccessibility of phenolics with genetic and genomic approaches will enable the identification of genotypes and genetic factors influencing these traits in blueberry.