Positive effects of ultrasound pretreatment on the bioaccessibility and cellular uptake of bioactive compounds from broccoli: Effect on cell wall, cellular matrix and digesta

Effect of pectin structure on the in vitro bioaccessibility of carotenoids in simulated juice model

The impact of pectin structure on carotenoid bioaccessibility is still uncertain. This study aims to investigate how the different pectic polymers affected the bioaccessibility of carotenoids in a simulated juice model during static in vitro digestion. This study includes homogalacturonan (HG), which is a linear pectic polymer, rhamnogalacturonan-I (RG-I), which is a branched pectic polymer, and rhamnogalacturonan (RG), which is a diverse pectic polymer rich in RG-I, rhamnogalacturonan-II (RG-II), and xylogalacturonan domains. Juice models without pectin had the highest carotenoid bioaccessibility, suggesting pectin has negative effects on carotenoid bioaccessibility. During the intestinal phase, systems with HG showed the highest viscosity, followed by systems with RG and systems with RG-I. Systems with RG-I had lower carotenoid bioaccessibility than systems with HG and RG-II. Both the percentage of RG-I and the average side chain length of RG-I had negative correlations with carotenoid bioaccessibility. RG-I side chains with more arabinose and/or galactose might cause lower carotenoid bioaccessibility in this juice model system. This study offers valuable insights into the relationship between pectin structure and carotenoid bioaccessibility in a simulated juice model, highlighting the importance of considering pectin composition for maximizing carotenoid bioaccessibility and potential health benefits in fruit-based beverages.

Polygalacturonase treatment affects carotenoid absorption from veggie juice

The present study was conducted to investigate the effects of polygalacturonase (PG) treatment on carotenoid absorption upon digestion of HPH-treated combined peach and carrot juice (CJ) with or without the presence of lipids. Results showed that PG treatment reduced median particle diameter (D₅₀) and viscosity of CJ, and increased total carotenoid bioaccessibility by 41%. In the presence of emulsion, the bioaccessibility of carotenoids was higher and it was not significantly affected by PG treatment. Xanthophylls (lutein and zeaxanthin) had higher bioaccessibility than the more lipophilic carotenes (β-carotene and α-carotene); also, uptake in Caco-2 cells and transport of lutein and zeaxanthin were higher than for β-carotene and α-carotene. Individual carotenoids bioaccessibility was negatively correlated with their transport. All together data showed digestion and absorption processes were two independent processes: factors improving carotenoid bioaccessibility did not necessarily affect their bioavailability.

Ultrasonic washing as an abiotic elicitor to increase the phenolic content in fruits and vegetables: A review

Ultrasonic washing has been widely applied to the postharvest storage of fruits and vegetables as a residue-free physical washing technology, which plays an important role in improving shelf-life, safety, and nutritional value. Phenolics are a large group of phytochemicals widespread in fruits and vegetables, and they have been considered potential protective factors against some diseases because of potent antioxidative properties. Previous studies have shown that ultrasonic washing can increase the phenolic content of fruits and vegetables immediately or during storage through the induction of plant stress responses, which is of great significance for improving the functional and nutritional value of fruits and vegetables. However, the mechanisms of ultrasound as an elicitor to improve the phenolic content remain controversial. Therefore, this review summarizes the applications of ultrasonic washing to increase the phenolic content in fruits and vegetables. Meanwhile, the corresponding physiological stress response mechanisms of the phenolic accumulation in terms of immediate stress responses (i.e., higher extractability of phenolics) and late stress responses (i.e., metabolism of phenolics) are expounded. Moreover, a hypothetical model is proposed to explain phenolic biosynthesis triggered by signaling molecules produced under ultrasound stress, including primary signal (i.e., extracellular adenosine triphosphate) and secondary signals (e.g., reactive oxygen species, Ca²⁺ , NO, jasmonates, and ethylene). Additionally, the techno-economic feasibility of ultrasonic washing technology is also discussed. Further, challenges and trends for further development of ultrasonic washing as an abiotic elicitor applied to the postharvest storage of fruits and vegetables are presented.