The aim of this work was to evaluate the phenolic compounds and antioxidant activity of goat milk yogurt characterized by different α-casein genotypes and fortified with Rhus coriaria leaf powder. The α-casein genotype was determined by isoelectric focusing, total phenol content was determined by the Folin-Ciocalteu method, phenolic compounds were identified and quantified by HPLC-UV analysis, and antioxidant activity was measured using 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid and ferric-reducing antioxidant power. The statistical analysis showed a significant effect of the studied factors. Comparing different genotypes it emerged that yogurt from goats with weak alleles at CSN1S1 loci (FF) showed the lowest phenolic compounds and therefore a lower antioxidant activity compared with yogurt from goats with strong alleles at CSN1S1 loci (AA, BB, AB). Rhus coriaria-fortified yogurt showed a significant increase in total phenolic compounds and antioxidant activity in comparison with plain yogurt. The FF-fortified yogurt presented the lowest total phenol content and antioxidant activity. This could be due to a greater capacity of proteins and peptides in this yogurt to form stable complexes with phenols. The different total phenol content detected in R. coriaria-fortified yogurt indicates that the α-casein genotype influenced the amount of added phenols that are bound to the caseins and, therefore, the part that remains free and that affects the biological capacity of the final product.

Goat yogurt samples fortified with 20% (w/v) Rhus coriaria leaf powder were in vitro digested in order to evaluate the total phenolic content (TPC), antioxidant activity (AA), and bioaccessibility of phenolic compounds in the digestate. After digestion, TPC and AA values of the R. coriaria-fortified yogurts increased compared to the undigested yogurts (P < 0.001). In particular, TPC has increased about twice; whereas, AA values have increased about 10 and 6 times, for ABTS and FRAP assays, respectively. The bioaccessibility index was well above the 100% for all identified phenols; except for (-)-epicatechin (82.04%), rutin (51.51%), and gallic acid (5.42%). This different behavior highlighted that the bioaccessibility was modulated by both the yogurt-polyphenol complexes and phenol stability under digestion system. These findings can contribute to elucidate the influence of in vitro digestion on antioxidant capacity and polyphenols recovery infortified yogurts, and may help in the design of dairy products with better functional quality Practical Application: Rhus coriaria L. (Sumac) is a polyphenol-rich Mediterranean plant that may be used as functional ingredient to enrich fermented food such as yogurt. However, in fortified yogurts the evaluation of bioaccessibility, that is, the compounds released from the yogurt and stable in the digestive environment, thus able to exert their biological effects on the gastrointestinal system, is more important than the content of these compounds in the corresponding food. This study highlighted the phenolic content, antioxidant activity, and bioaccessibility of phenolic compounds in goat milk yogurt fortified with R. coriaria leaf powder after simulated gastro-pancreatic digestion.

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The aim of the present study was to evaluate the effect of high pre-slaughter environmental temperature on meat (Longissimus lumborum muscle) quality traits of Italian autochthonous pigs Suino Nero Lucano (SNL). High pre-slaughter environmental temperature influenced the meat quality of autochthonous pigs. In particular, the meat from SNL pigs exposed to heat stress (H) showed significantly lower pH values at 24 and 48 hr post mortem, haem iron content and redness (a*) value, and a significantly higher shear force, drip loss and lightness (L*) values, compared to meat from SNL pigs reared under comfortable environmental temperature (C). Moreover, H meat showed a significant reduction of vitamin A, vitamin E, creatine and carnosine content, compared to C meat. Despite this, no pale-soft-exudative pork was found in our study, and no significant difference was detected between two studied groups for intramuscular fat and protein content of meat. In addition, despite the meat from SNL pigs exposed to heat stress has suffered a qualitative decrease, it showed a good endogenous antioxidants content.

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