In Vitro Evidence on Bioaccessibility of Flavonols and Cinnamoyl Derivatives of Cruciferous Sprouts

Abstract

Cruciferous sprouts are rising in popularity as a hallmark of healthy diets, partially because of their phytochemical composition, characterized by the presence of flavonols and cinnamates. However, to shed light on their biological activity, the ability to assimilate (poly)phenols from sprouts (bioaccessible fraction) during gastrointestinal digestion needs to be studied. In this frame, the present work studies the effect of the physicochemical and enzymatic characteristics of gastrointestinal digestion on flavonols and cinnamoyl derivatives, by a simulated static in vitro model, on different cruciferous (red radish, red cabbage, broccoli, and white mustard) sprouts. The results indicate that, although the initial concentrations of phenolic acids in red radish (64.25 mg/g fresh weight (fw)) are lower than in the other sprouts studied, their bioaccessibility after digestion is higher (90.40 mg/g fw), followed by red cabbage (72.52 mg/g fw), white mustard (58.72 mg/g fw), and broccoli (35.59 mg/g fw). These results indicate that the bioaccessibility of (poly)phenols is not exclusively associated with the initial concentration in the raw material, but that the physico-chemical properties of the food matrix, the presence of other additional molecules, and the specific characteristics of digestion are relevant factors in their assimilation.

A New Food Ingredient Rich in Bioaccessible (Poly)Phenols (and Glucosinolates) Obtained from Stabilized Broccoli Stalks

“…As referred to before, the present article pursues uncovering the influence of the stabilizing broccoli stalks regarding their quantitative profile of bioactive phytochemicals using different time-temperature conditions and, thus, identifying the best option to retrieve the highest amount of bioaccessible bioactive phenolics and organosulfur (ITC and nitriles) compounds. This issue deserves to be explored because, despite the cumulative evidence concerning the bioaccessibility of both types of bioactive compounds [ 13 , 17 ], there is no information on the relevance of the different starting phytochemical burdens to obtain significantly higher concentrations in the intestinal lumen available to be absorbed.…”

“…For this purpose, samples (100 mg) were first homogenized in 1 mL of ethanol/deionized water (50:50, v / v ) and then extracted (i) at 70 °C, for 20 min, with vortex shaking every 5 min. All the obtained extracts were centrifuged at 4000 rpm, for 5 min, filtered through a 0.22 μm PVDF filter (Millipore, MA, USA), and kept at −20 °C until chromatographic analysis [ 13 , 17 ].…”

“…The chromatographic separation and spectrometry analysis of GSL and phenolic compounds present in the analytical extracts and gastrointestinal digestion products was performed following the methodology described by Baenas et al and Abellán et al [ 16 , 23 ]. The tentative identity of the phenolic compounds and GSL was attained according to the retention time (min), parent ions, and fragmentation patterns, in comparison with authentic standards and descriptions available in the literature [ 17 ] ( Supplementary Tables S1 and S2 ). The quantification was performed on chromatograms recorded at 330 nm (phenolic acids) and 227 nm (GSL), applying calibration curves freshly prepared each day of analysis.…”

“…The health-promoting activity is commonly ascribed, not only to a single compound, but also to a group of bioactive phytochemicals in the food matrix (e.g., kaempferol glycosides or hydroxycinnamic acid derivatives [ 14 , 15 ]) that may contribute to the capacity to scavenge reactive oxygen species (ROS) and, thus, reducing oxidative stress and mutagenic events [ 16 ]. Indeed, both types of compounds (organosulfur and phenolics) provide complementary bioactivities that boost the final health benefits of cruciferous foods [ 17 ]. Therefore, to take advantage of these biological functions, the adjustment of the processing protocols to gain a stable and safe product, maintaining the highest amount of original compounds possible, remains crucial [ 3 ].…”

“…To evaluate the effect of gastrointestinal digestion on the stability of broccoli phytochemicals and, thereby, on the biological interest of broccoli derived ingredients, the design of a proper processing method supported by sensitive analysis of phenolics and GSL/ITC is needed. Additionally, the study of the processing effects in combination with the physicochemical during the gastrointestinal digestion [ 13 , 17 ], would allow retrieving specific bioaccessible phytochemical profiles with multiple benefits on health [ 21 ].…”