Elderly gastrointestinal conditions increase sterol bioaccessibility in a plant sterol-enriched beverage: adaptation of the INFOGEST method

Lipolysis and Sterol Stability and Bioaccessibility of Wholemeal Rye Bread Enriched with Plant Sterols Subjected to Adult and Elderly Digestion Conditions

This study evaluated the impact of different digestion conditions (adult and senior) on lipolysis and bioaccessibility of plant sterols (PS) and phytosterol oxidation products (POPs) in PS-enriched wholemeal rye bread. Under adult digestion conditions, the addition of gastric lipase (GL) reduced lipolysis products (by 6.1% for free fatty acids and 11.7% for monoacylglycerols) and the bioaccessibility of PS by 6.7%, compared to the control. In digestion with both GL and cholesterol esterase (CE), these reductions were 12.9, 20.1, and 11.3%, respectively. Both modifications (GL and GL + CE) increased the bioaccessibility of POPs by 4.5-4.0%. When simulating the elderly digestion, the modified gastric and intestinal phases did not alter PS bioaccessibility but decreased POPs bioaccessibility by 21.8% compared to control, along with reduced lipolysis. Incorporating GL and CE thus approached physiological conditions and influenced lipid digestion. Elderly simulated digestion conditions resulted in a positive outcome by maintaining PS bioaccessibility while reducing potentially harmful POPs.

Application of small angle X-ray scattering in exploring the effect of edible oils with different unsaturation FAs on bioaccessibility of stigmasterol oleate

BACKGROUND

Phytosterol can improve its lipid solubility, lipophilic/hydrophilic balance and bioaccessibility by esterification with fatty acids, which increases its practical application range in the food industry. In the present study, small angle X-ray scattering combined with the pH-stat in vitro digestion model was applied to continuously monitor the molecular structure evolution of mixed micelles during digestion and investigate the effect of three edible oils (olive oil with 72.41 ± 0.57% oleic, sunflower seed oil with 63.45 ± 0.78% linoleic, refined linseed oil with 51.74 ± 0.34% linolenic) on bioaccessibility of stigmasterol oleate in vitro.

RESULTS

The release degree and rate of fatty acids in the three edible oil systems (kOO+ST-OA  = 0.0501, kSO+ ST-OA  = 0.0357, kLO+ST-OA  = 0.0323) was compared. The three different edible oils had similar impact on the formation of dietary mixed micelles during the simulatedin vitro digestion of stigmasterol oleate, although there were significant differences in molecular morphology and composition of mixed micelles. The results showed that the vesicles formed by linoleic oil (SO system) or linolenic oil (LO system) were easy to dissociate. The largest average number and diameter of vesicles (5.55 × 1016  cm-3 and 2230.75 Å), the most stable vesicle structure and the fastest fatty acid release rate were observed in the OO system.

CONCLUSION

Compared to linoleic (SO system) or linolenic (LO system), the oleic (OO system) could facilitate the transformation of micelles to vesicles and maintain the stability of its membrane, significantly promotin the dissolution of stigmasterol and improving bioaccessibility. © 2023 Society of Chemical Industry.

Study on the synthesis of pine sterol esters in solvent-free systems catalyzed by Candida rugosa lipase immobilized on hydrophobic macroporous resin

BACKGROUND

Pine sterol ester is a type of novel food source nutrient with great advantages in lowering blood cholesterol levels, inhibiting tumors, preventing prostate enlargement, and regulating immunity. Macroporous resins with large specific surface area, stable structures, and various functional groups (epoxy, amino, and octadecyl groups) have been selected for immobilization of Candida rugosa lipase (CRL) to improve its stability and efficiency in the synthesis of pine sterol esters. A solvent-free strategy using oleic acid (substrate) as an esterification reaction medium is an important alternative for avoiding the use of organic solvents.

RESULTS

The immobilization conditions of CRL immobilized on several types of commercial macroporous resins were optimized. Fortunately, by adsorption (hydrophobic interaction), a high immobilization efficiency of CRL was obtained using macroporous resins with hydrophobic octadecyl groups with an immobilization efficiency of 86.5%, enzyme loading of 138.5 mg g-1 and enzyme activity of 34.7 U g-1 . The results showed that a 95.1% yield could be obtained with a molar ratio of oleic acid to pine sterol of 5:1, an enzyme amount of 6.0 U g-1 (relative to pine sterol mass) at 50 °C for 48 h.

CONCLUSION

The hydrophobic macroporous resin (ECR8806M) with a large specific surface area and abundant functional groups was used to achieve efficient immobilization of CRL. CRL@ECR8806M is an efficient catalyst for the synthesis of phytosterol esters and has the potential for further large-scale applications. Therefore, this simple, green, and low-cost strategy for lipase immobilization provides new possibilities for the high-efficiency production of pine sterol esters and other food source nutrients. © 2023 Society of Chemical Industry.

Evaluation of Pure Bile Salts in Place of Bile Extract in the Standardized INFOGEST Digestion Protocol for Quantification of Sterol Bioaccessibility

Improving standardized in vitro digestion protocols for phytosterols (PSs) is critical for understanding their bioaccessibility (BA) in food products and supplements. In this study, in vitro BA of phytosterol esters (PSEs) and free cholesterol (Ch) was compared under modified digestion conditions. The addition of Ch esterase (CE) to the INFOGEST model containing bovine bile resulted in a 70% increase in PS BA and an 18.5% reduction in Ch micellarization. Relative to the standardized INFOGEST model, substitution of pure bile salts (PBSs) did not significantly change PS BA or Ch micellarization. In the presence of CE, the substitution resulted in a 49.9% reduction in PS BA and a 13% increase in Ch micellarization. The differing results may be due to inhibitory effects of PBSs on the activity of intestinal enzymes, including CE. These results suggest that the INFOGEST model should include Ch esterase and the continued use of bile extract to evaluate PS BA.