Macronutrient digestion and polyphenol bioaccessibility in oat milk tea products: an in vitro gastrointestinal tract study.

People are increasingly preparing milk tea using plant-based milks rather than cow's milk, e.g., vegans, those with lactose intolerance, and those with flavor preferences. However, adding plant-based milks to tea may impact the digestion, release, and bioaccessibility of nutrients and nutraceuticals in both the tea and milk. In this study, oat milk tea model systems (OMTMSs) containing different fat and tea polyphenol concentrations were used to explore the impact of tea on macronutrient digestion in oat milk, as well as the impact of oat milk matrix on the polyphenol bioaccessibility in the tea. An in vitro gastrointestinal model that mimics the mouth, stomach, and small intestine was used. Tea polyphenols (>0.25%) significantly reduced the glucose and free fatty acids released from oat milk after intestinal digestion. Tea polyphenols (>0.10%) also inhibited protein digestion in oat milk during gastric digestion but not during intestinal digestion. The bioaccessibility of the polyphenols in the tea depended on the fat content of oat milk, being higher for medium-fat (3.0%) and high-fat (5.8%) oat milk than low-fat (1.5%) oat milk. Liquid chromatography-tandem mass spectrometry (UPLC-ESI-MS/MS) analysis showed that lipids improved the tea polyphenol bioaccessibility by influencing the release of flavonoids and phenolic acids from the food matrices. These results provide important information about the impact of tea on the gastrointestinal fate of oat milk, and vice versa, which may be important for enhancing the healthiness of plant-based beverages.

Oat Milk Tea Model System: Exploring the Stability of Milk Tea and the Bioaccessibility of Green Tea Polyphenols.

Oat milk has become preferential because of its low calorie nature and high dietary fiber content, but its ability to "curdle" when mixed with tea can affect the consumer acceptability for oat milk tea. In this study, a model system for oat milk tea was made by combining oat milk and green tea extract to evaluate the impacts of the oat milk matrix and green tea extract concentration on the stability and polyphenol bioaccessibility. The stability analysis results showed that adding green tea extract to oat milk influenced the stability of the oat milk tea model systems. In contrast, the 3.0% fat oat milk tea model system exhibited a higher stability than the 1.5% fat oat milk tea model system. In simulated gastrointestinal digestive experiments, tea polyphenols in the oat milk tea model systems were relatively stable in oral and stomach digestive stages, while they clearly degraded in the small intestine digestive stage. Furthermore, the bioaccessibility of tea polyphenols was higher for the 3.0% fat oat milk tea model system than for the 1.5% fat oat milk tea model system, especially at low concentrations of green tea extracts (0.05%~0.25%). These results may provide a theoretical reference and data for the formulation of oat milk tea and the bioaccessibility of tea polyphenols in food matrices.

[UPLC fingerprint and multi-components determination of three processed products of Rhizome of Curcuma wenyujin].

To analyse the quality of three processed products of Rhizome of Curcuma wenyujin by establishing an ultra performance liquid chromatography (UPLC) method for simultaneously determining five sesquiterpene components in three processed products of rhizome of C. wenyujin and establishing UPLC fingerprints. Component determination was achieved on Waters ACQUITY UPLC BEH C18 column（2.1 mm×50 mm, 1.7 µm), with acetonitrile-water as mobile phase for gradient elution. The flow rate was 0.3 mL·min⁻¹; column temperature was 30 °C; the detection wavelength was set at 214 nm and injection volume was 1 µL. The similarity was analyzed with "Similarity Evaluation System for Chromatographic Fingerprint of Chinese Materia Medica (2012.130723)", and hydrophobic cluster analysis (HCA), principal components analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were conducted by using simca-p14.1 software to investigate the differences in components among these three kinds of processed products. The curzerene, curdione, curcumol, germacrone, furanodiene and ß-elemene showed good linearity relationship with chromatographic peak area within the ranges of 10.8-320（r=0.999 9）, 10.36-259（r=0.998 1）, 10.54-263.5（r=0.999 3）, 30.2-755（r=0.999 6）and 34.38-862（r=0.999 9）mg·L⁻¹, respectively; their average recoveries were 98.75%, 98.69%, 98.63%, 99.76% and 99.57% respectively, with RSD of 2.67%, 1.47%, 1.29%, 2.54% and 0.87% respectively. The similarity of 30 batches of samples was larger than 0.9, indicating good consistency of the samples. The samples can be clearly classified into three categories for HCA, PCA and OPLS-DA pattern recognition, the differential chromatographic peak among three processed products was found respectively. The results showed that the pharmacology basis had changed obviously after processing of Rhizome of C. wenyujin, so it can provide the scientific basis for rational clinical application and establishing quality standards of three processed products of Rhizome of curcuma wenyujin.