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- Optimisation, by response surface methodology, of degree of hydrolysis and antioxidant and ACE-inhibitory activities of whey protein hydrolysates obtained with cardoon extractPublication . Tavares, T. G.; Contreras, M. M.; Amorim, M.; Martín-Álvarez, P. J.; Pintado, M. E.; Recio, I.; Malcata, F. X.The hydrolysis of bovine whey protein concentrate (WPC), alpha-lactalbumin (alpha-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 alpha-La, but not from CMP. Maximum DH was 18% and 9%, for WPC and alpha-La, respectively. 50% ACE-inhibition was produced by 105.4 (total fraction) and 25.6 mu g mL(-1) (<3 kDa fraction) for WPC, and 47.6 (total fraction) and 22.5 mu g mL(-1) (<3 kDa fraction) for alpha-La. Major peptides of fractions exhibiting ACE-inhibition were sequenced. The antioxidant activities of WPC and alpha-La were 0.96 +/- 0.08 and 1.12 +/- 0.13 mmol trolox equivalent per mg hydrolysed protein, respectively.
- Invited review: physiological properties of bioactive peptides obtained from whey proteinsPublication . Madureira, A. R.; Tavares, T.; Gomes, A. M. P.; Pintado, M. E.; Malcata, F. XavierProcessing 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.
- Manufacture of bioactive peptide-rich concentrates from whey: characterization of pilot processPublication . Tavares, Tânia G.; Amorim, Manuela; Gomes, David; Pintado, Manuela E.; Pereira, Carlos D.; Malcata, F. XavierThis work was focused on the manufacture, at pilot scale, of cow whey protein and peptide concentrates, using selective filtration techniques—associated with hydrolysis brought about by proteolytic enzymes from Cynara cardunculus aqueous extracts, using as (optimal) conditions an enzyme/substrate ratio of 1.6% v/v, a pH of 5.2, a temperature of 55 C and an incubation time of 7 h. The profiles of proteins and peptides were assessed by liquid chromatography and electrophoresis; ca. 87% of a-lactalbumin was hydrolyzed, but essentially no degradation of b-lactoglobulin (b-Lg) was observed. A bioactive peptide concentrate, its fraction below 3 kDa and a b-Lg-rich fraction were obtained as final products, containing ca. 73, 43 and 91% w/w protein (on a total solid mass basis). All these fractions were low in lactose and salt, and their microbial loads were reduced. Said fractions are high added-value products, so they can be used as nutritional and functional ingredients—thus yielding an economically viable alternative for upgrade of whey.
- Bioactivity of probiotic whey cheese: characterization of the content of peptides and organic acidsPublication . Madureira, Ana R.; Soares, José C.; Amorim, Maria; Tavares, Tania; Gomes, Ana M.; Pintado, Maria M.; Malcata, F. XavierBackground Probiotic whey cheeses have been produced for several years. It is recognized that several bacterium-mediated metabolic activities contribute differently to the final sensory and nutritional profiles of dairy products. Hence the metabolic activity of probiotic strains in a whey cheese and their contribution to the bioactivity of such matrices were investigated here, including in particular Bifidobacterium animalis, Lactobacillus acidophilus and Lactobacillus casei. Results Both L. casei and B. animalis produce lactic and acetic acids, whereas L. acidophilus produce mainly lactic acid; these metabolites may be considered bioprotection factors. Water-soluble extracts (WSE) obtained from these cheese matrices were subjected to ultrafiltration through a 3 kDa cut-off membrane, and the eluted peptides were resolved by high-performance liquid chromatography. Different qualitative and quantitative profiles were obtained, depending on the strain. WSE were further assayed for their ability to inhibit angiotensin-converting enzyme; the <3 kDa fraction exhibited higher activities in the case of L. casei and B. animalis than the control and L. acidophilus. Conclusion Whey cheeses with higher nutritional value were those inoculated with L. casei.
- The Portuguese Paradox: why do some inhabitants of Portugal appear to live so long when their diet is based on whey cheese?Publication . Tavares, Tânia G.; Malcata, F. XavierThe remarkable longevity of people in specific regions of Portugal, whose diets are based on whey cheese, has puzzled researchers for quite some time. Our data indicate that several oligopeptides are released from glycomacropeptide (originated in j-casein) and a-lactalbumin – and one surprisingly from b-lactoglobulin, by plant proteases previously used in cheesemaking. A few of such peptides (e.g. DKVGINYW, KGYGGVSLPEW and DAQSAPLRVY) exhibit unusually strong antihypertensive roles in vitro, following generation in situ or synthesis de novo. The activities of the latter two are not significantly affected by simulated gastrointestinal digestion, despite undergoing partial hydrolysis. This piece of information is rather promising toward more comprehensive attempts to scientifically rationalise this Portuguese Paradox.
- Antiulcerogenic activity of peptide concentrates obtained from hydrolysis of whey proteins by proteases from Cynara cardunculusPublication . Tavares, T.G.; Monteiro, K.M.; Possenti, A.; Pintado, M. E.; Carvalho, J. E.; Malcata, F. XavierPeptide concentrates generated by hydrolysis of whey with aqueous extracts of flowers of Cynara cardunculus were studied for possible protection of the stomach mucosa against ulcerative lesions caused by oral administration of absolute ethanol. Both the whole peptide fraction obtained via hydrolysis of whey protein concentrate (peptide concentrate, PepC) and its fraction below 3 kDa (PepCF) were able to reduce gastric injuries to significant levels (p < 0.05). Single-dose experiments, using 100 mg kg(-1) body weight (bw) of either PepCF or PepC, led to 68.5% and 37.4% protection, respectively - which compare well with 93.4% protection by 200 mg kg (1) bw carbenoxolone (a positive control). No dose-response correlation could be demonstrated. Gastric cytoprotection by PepCF appears to depend on sulphydryl-containing moieties, whereas PepC likely protects the gastric mucosa via the prostaglandin cycle and production of nitric oxide.
- Antinociceptive and anti-inflammatory effects of novel dietary protein hydrolysate produced from whey by proteases of Cynara cardunculusPublication . Tavares, T. G.; Spindola, H.; Longato, G.; Pintado, M. E.; Carvalho, J. E.; Malcata, F. X.Antinociceptive and anti-inflammatory effects of a peptide concentrate mix (PepC) obtained from whey protein, via hydrolysis with cardosins from Cynara cardunculus, was tested in vivo. The antinociceptive effect was assessed using writhing, hot-plate and formalin tests in mice, and the anti-inflammatory effect using the paw oedema test. PepC at 300 mg kg(-1) bw conveyed a significant result in the writhing test when co-administered with 1 and 3 mg kg(-1) bw indomethacin, similar to administration of higher doses of indomethacin alone. Conversely, no statistically significant differences were observed in the paw oedema test when the same PepC concentration was co-administered with dexamethasone at 3, 10 and 30 mg kg(-1) bw. PepC at 1000 mg kg(-1) bw did not cause any remarkable outcome in the hot-plate test. PepC appears to possess anti-inflammatory and peripheral antinociceptive activities, so it may be a candidate for nutraceutical ingredient.