Processing of whey proteins yields several bioactive peptides that can trigger physiological effects in the human body: on the nervous system via their opiate and ileum-contracting activities; on the cardiovascular system via their antithrombotic and antihypertensive activities; on the immune system via their antimicrobial and antiviral activities; and on the nutrition system via their digestibility and hypocholesterolemic effects. The specific physiological effects, as well the mechanisms by which they are achieved and the stabilities of the peptides obtained from various whey fractions during their gastrointestinal route, are specifically discussed in this review.

a b s t r a c tWhey protein concentrate (WPC) was subjected to enzymatic hydrolysis by proteases from the flowers of Cynara cardunculus, and the resulting angiotensin-converting enzyme (ACE)-inhibitory effect was monitored. The whole WPC hydrolysate exhibited an IC 50 value of 52.9 ± 2.9 g/mL, whereas the associated peptide fraction with molecular weight below 3 kDa scored 23.6 ± 1.1 g/mL. The latter fraction was submitted to RP-HPLC, and 6 fractions were resolved that exhibited ACE-inhibitory effects. Among the various peptides found, a total of 14 were identified via sequencing with an ion-trap mass spectrometer. Eleven of these peptides were synthesized de novo -to validate their ACE-inhibitory effect, and also to ascertain their stability when exposed to simulated gastrointestinal digestion. Among them, three novel, highly potent peptides were found, corresponding to ␣-lactalbumin f(16-26) -with the sequence KGYGGVSLPEW, ␣-lactalbumin f(97-104) with DKVGINYW, and ␤-lactoglobulin f(33-42) with DAQS-APLRVY; their IC 50 values were as low as 0.80 ± 0.1, 25.2 ± 1.0 and 13.0 ± 1.0 g/mL, respectively. None of them remained stable in the presence of gastrointestinal enzymes: they were partially, or even totally hydrolyzed to smaller peptides -yet the observed ACE-inhibitory effects were not severely affected for two of those peptides.

Cheesemaking from batches of raw ewe's milk was carried out via inoculation with wild strains of Lactococcus lactis subsp. lactis ESB110019 and Lactobacillus plantarum ESB5004 independently, or combined with each other. Those two strains had been isolated from the native microflora of typical Serra da Estrela cheese. One control batch was processed in parallel without addition of any starter. The evolution in viable counts of the main microorganisms (viz. lactic acid bacteria, Enterobacteriaceae, staphylococci and yeasts), as well as in secondary proteolysis (WSN, 2% TCASN, 12% TCASN and 5% PTASN), was monitored throughout ripening time (over a 63-day period) in cheeses from each batch. The sensory features of the fully ripened cheeses were also assessed. Cheeses manufactured with starter showed significantly lower levels of viable Enterobacteriaceae than those manufactured without starter; viable counts of enterococci and staphylococci did significantly increase after addition of L. lactis or Lb. plantarum, respectively. Proteolysis in terms of WSN and 5% PTASN was not significantly affected by the lactic acid bacteria tested when compared to the control, but L. lactis played a significant role toward increasing the 2% TCASN content of cheeses; both strains led to a statistically significant increase of the 12% TCASN. The scores for flavor and texture of the control cheeses were somewhat above those for the experimental cheeses manufactured with starter.

a b s t r a c tThe hydrolysis of bovine whey protein concentrate (WPC), a-lactalbumin (a-La) and caseinomacropeptide (CMP), by aqueous extracts of Cynara cardunculus, was optimized using response surface methodology. Degree of hydrolysis (DH), angiotensin-converting enzyme (ACE)-inhibitory activity and antioxidant activity were used as objective functions, and hydrolysis time and enzyme/substrate ratio as manipulated parameters. The model was statistically appropriate to describe ACE-inhibitory activity of hydrolysates from WPC and a-La, but not from CMP. Maximum DH was 18% and 9%, for WPC and a-La, respectively. 50% ACE-inhibition was produced by 105.4 (total fraction) and 25.6 mg mL À1 (<3 kDa fraction) for WPC, and 47.6 (total fraction) and 22.5 mg mL À1 (<3 kDa fraction) for a-La. Major peptides of fractions exhibiting ACEinhibition were sequenced. The antioxidant activities of WPC and a-La were 0.96 AE 0.08 and 1.12 AE 0.13 mmol trolox equivalent per mg hydrolysed protein, respectively.

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Our results strongly suggest that PepC will be effective as nutraceutical ingredient for the formulation of functional foods aimed at hypertension control.

Whey cheeses with higher nutritional value were those inoculated with L. casei.

The contributions of the coagulant Cynara cardunculus and of the microflora of raw milk to the volatile-free fatty acid profile of Serra da Estrela cheese were evaluated. The experimental design included both a model system and, dual cheeses. The study in the model system showed that isovaleric acid was the predominant volatile compound after 7 d of ripening. The systems inoculated with Enterococcus faecium produced the highest amount of this volatile (ca. 135.8 mg kg À1 curd), while those inoculated with Lactobacillus plantarum produced the least (21.4 mg kg À1 curd); Lactococcus lactis produced moderate amounts (ca. 34.2 mg kg À1 curd) but a total amount of volatile-free fatty acids similar to those found in control samples. This is considered advantageous since this volatile fatty acid confers a harsh, piquant, mature flavour to cheese, coupled with the realisation that excess volatiles may result in off-flavours. The addition of cultures in experimental cheeses helped reduce ripening time to about one half. Inclusion of Lb. plantarum led to cheeses containing the highest amounts of volatiles, and exhibiting an aroma closest to that of typical Serra da Estrela cheese. r