M.C. Sánchez-Mata

α-Solasonine and α-solamargine contents of gboma (Solanum macrocarpon L.) and scarlet (Solanum aethiopicum L.) eggplants.

The gboma (Solanum macrocarpon L.) and scarlet eggplants (Solanum aethiopicum L.), which form part of the traditional sub-Saharan African culture, are two of the many neglected crops with potential for increased cultivation or as a genetic resource for improving agronomic traits of the common eggplant. This work is focused on the analysis of glycoalkaloid levels in S. macrocarpon and S. aethiopicum to assess their safety. Liquid chromatography-mass spectrometry was used to quantify glycoalkaloids in S. macrocarpon and S. aethiopicum compared to Solanum melongena L. Fruits of S. aethiopicum and S. melongena contained 0.58-4.56 mg/100 g of alpha-solamargine and 0.17-1 mg/100 g of alpha-solasonine, on a wet basis. S. macrocarpon fruits had much higher values of alpha-solamargine (124-197 mg/100 g) and alpha-solasonine (16-23 mg/100 g). However, the proportions of alpha-solamargine and alpha-solasonine of S. melongena and S. macrocarpon were similar (76-89% of alpha-solamargine), whereas in S. aethiopicum fruit composition was more variable (48-89% of alpha-solamargine). According to these results, the glycoalkaloid levels of S. macrocarpon fruits are 5-10 times higher than the value considered to be safe in foods and might not be considered suitable for human consumption; however, the glycoalkaloid levels of S. aethiopicum were similar to those of S. melongena (about 14% of values considered as toxic) and could be considered as safe for consumption. The incorporation of the cultivated African S. aethiopicum into eggplant breeding programs to develop improved varieties of the common eggplant may represent an alternative to crossing with wild species.

Matching in Vitro Bioaccessibility of Polyphenols and Antioxidant Capacity of Soluble Coffee by Boosted Regression Trees.

The aim of this study was to evaluate changes in polyphenol profile and antioxidant capacity of five soluble coffees throughout a simulated gastro-intestinal digestion, including absorption through a dialysis membrane. Our results demonstrate that both polyphenol content and antioxidant capacity were characteristic for each type of studied coffee, showing a drop after dialysis. Twenty-seven compounds were identified in coffee by HPLC-MS, while only 14 of them were found after dialysis. Green+roasted coffee blend and chicory+coffee blend showed the highest and lowest content of polyphenols and antioxidant capacity before in vitro digestion and after dialysis, respectively. Canonical correlation analysis showed significant correlation between the antioxidant capacity and the polyphenol profile before digestion and after dialysis. Furthermore, boosted regression trees analysis (BRT) showed that only four polyphenol compounds (5-p-coumaroylquinic acid, quinic acid, coumaroyl tryptophan conjugated, and 5-O-caffeoylquinic acid) appear to be the most relevant to explain the antioxidant capacity after dialysis, these compounds being the most bioaccessible after dialysis. To our knowledge, this is the first report matching the antioxidant capacity of foods with the polyphenol profile by BRT, which opens an interesting method of analysis for future reports on the antioxidant capacity of foods.

Intestinal bioaccessibility of polyphenols and antioxidant capacity of pulp and seeds of cactus pear

The aim of this work was to estimate the intestinal bioaccessibility of polyphenols and antioxidant capacity of cactus pear using an in vitro gastrointestinal model. The amount of polyphenols released from the food matrix by the action of digestive enzymes was about 69–83% in pulp and 0–14% in seeds. The rest of polyphenols was associated with indigestible compounds conferring antioxidant capacity. The results suggest that these compounds could reach the colon and induce healthy effects.