Anna Maria Perna

What Are the Proteolytic Enzymes of Honey and What They Do Tell Us? A Fingerprint Analysis by 2-D Zymography of Unifloral Honeys

Honey is a sweet and healthy food produced by honeybees (Apis mellifera L.) from flower nectars. Using bidimensional zymography, we have detected the, until now unrevealed, proteolytic activities present in row honey samples. The resulting zymograms were specific for each type of the four unifloral honey under study, and enzymes were identified as serine proteases by the use of specific inhibitors. Further, using bidimensional electrophoresis, we have shown that honey proteases are able to degrade the major Royal Jelly proteins and in particular MRPJ-1, the protein that promotes queen differentiation in honeybees. Our findings open new perspectives for the better understanding of honeybee development, social behaviour and role in honey production. The now discovered honey proteases may influence honey properties and quality, and bidimensional zymograms might be useful to distinguish between different honey types, establish their age and floral origin, and allow honey certification.

Antioxidative and antihypertensive activities of pig meat before and after cooking and in vitro gastrointestinal digestion: Comparison between Italian autochthonous pig Suino Nero Lucano and a modern crossbred pig.

The aim of this study was to evaluate and compare antioxidative and antihypertensive activities of Longissimus dorsi muscle from Suino Nero Lucano (SNL) and a modern crossbred (CG) pigs, before and after cooking and in vitro gastrointestinal digestion. Pig meat showed antioxidative and antihypertensive activities, heat treatment decreased the thiols content but at the same time increased angiotensin I-converting enzyme (ACE) inhibitory activity, and in vitro gastrointestinal digestion enhanced the biological activity of meat. Autochthonous SNL meat showed a higher nutraceutical quality compared to CG meat, highlighting a greater potential beneficial physiological effect on human health. The results of this study indicate that the pig meat, in particular autochthonous pig meat, may be considered a functional food since it is a good source of antioxidative and antihypertensive peptides.

Effects of genetic type, stage of lactation, and ripening time on Caciocavallo cheese proteolysis

The objective of this experiment was to evaluate the effects of genetic type, stage of lactation, and ripening time on proteolysis in Caciocavallo cheese. One hundred twenty Caciocavallo cheeses made from the milk of 2 breeds, Italian Brown and Italian Holstein and characterized by different stages of lactation were obtained and ripened for 1, 30, 60, 90, and 150d. Cheese proteolysis was investigated by ripening index (ratio of water-soluble N at pH 4.6 to total protein, %) and by the study of degradation of the protein fractions (αS1-, β-, and para-κ-casein), which was determined by densitometric analysis of isoelectric focusing results. The statistical analysis showed a significant effect of the studied factors. Ripening index was higher in Italian Brown Caciocavallo cheese and in cheeses made with early lactation milk, whereas casein solubilization was greater in the first 2mo of ripening. Isoelectric focusing analysis of cheese samples during ripening showed extensive hydrolysis of caseins. In particular, the protein fraction that underwent major degradation by proteolytic enzymes was αS1-casein, followed by β-casein, whereas para-κ-casein was less degraded. Italian Brown cheese showed a lower residual quantity of β- and para-κ-casein, whereas Italian Holstein cheese showed a lower residual quantity of αS1-casein. In addition, significant interactions of both first and second order were found on both ripening index and degradation of protein fractions. This study demonstrated that the analyzed factors influenced proteolysis of Caciocavallo cheese, which forms the basis of new knowledge that could lead to the production of a pasta filata cheese with specific characteristics.

Fatty acids composition, cholesterol and vitamin E contents of Longissimus dorsi and Semitendinosus muscles of Suino Nero Lucano pigs slaughtered at two different weights

The nutritional quality of the lipid fraction of two muscles (Longissimus dorsi and Semitendinous) from Italian autochthonous genotype Suino Nero Lucano pigs slaughtered at two different weights was evaluated. Meat of Suino Nero Lucano pig showed a relatively low content of cholesterol and a higher proportion of unsaturated (UFA) than saturated fatty acids (SFA). Total cholesterol content was influenced by muscle, being higher in Longissimus dorsi (LD) than in Semitendinous (ST) muscle. No significant effects related to slaughter weight or muscle were found regarding vitamin E content. Slaughter weight strongly influenced n-3 and n-6 polyunsaturated fatty acids (PUFA) contents that decreased with increasing weight, and consequently, PUFA/SFA ratio. Muscle markedly influenced the contents of SFA, monounsaturated fatty acids (MUFA), and PUFA, and the dietetic properties of the meat. ST muscle, compared with the LD muscle, showed higher PUFA/SFA and PUFA n-6/PUFA n-3 ratios, and lower atherogenic and thrombogenic indices.

Quality and sensory characteristics of Culatello dry-cured products obtained from the Italian autochthonous pig Suino Nero Lucano and from a modern crossbred pig

The effect of the Suino Nero Lucano (SNL) pig genotype and crossbred genotype (CG) on chemical composition, fatty acid profile, oxidative stability, and sensory characteristics of 30 Culatello samples (15 from SNL and 15 from CG pigs) was investigated. SNL pigs showed a slower growth and therefore were older and lighter at slaughter. Samples from SNL pigs showed significantly (P < 0.001) higher amounts of haem iron, intramuscular fat, and monounsaturated fatty acids than those from CG. The oxidative stability, evaluated by measuring the acid, peroxide and TBARS values, was significantly larger in SNL than in CG Culatello. Moreover, Culatello from SNL pigs showed the highest level of consumer preference in term of overall acceptability (P < 0.05), odour (P < 0.001), taste (P < 0.01), appearance (P < 0.05), and consistency (P < 0.01). The present study confirms that the SNL pig represents a useful resource both for the obtainment of products with high nutritional and sensory value and for promoting the economic development of areas where they are raised.

The influence of casein haplotype on quality, coagulation, and yield traits of milk from Italian Holstein cows

The aim of this work was to investigate the effect of casein haplotype (CSN1S1, CSN2, and CSN3) on quality, coagulation, and yield traits of milk from Italian Holstein cows. The casein haplotype was determined by isoelectric focusing; milk clotting properties were determined by using a mechanical lacto-dynamographic instrument; and the yields of pressed and pasta filata cheeses were expressed as kilograms of cheese per 100kg of milk processed. Statistical analysis showed a significant effect of the casein haplotype. In particular, BB-A(1)A(1)-AA milk showed the highest fat content (4.01g/100g), whereas BB-A(2)A(2)-BB milk had a higher protein content, the best coagulation characteristics, and the highest yields in pressed and pasta filata cheeses, and, consequently, better ability to retain fat and protein in the curd. The results of this study suggest that knowledge of milk protein polymorphisms not only allows the production of milk with specific qualitative and quantitative characteristics, but it could also be used as a specific marker within a breed to identify milk suitable for cheesemaking, which confers an economical advantage for dairy producers.

Variability of the IGF2 locus in the Suino Nero Lucano pig population and its effects on meat quality

The aim of this study was to analyse the polymorphisms in the two promoter regions, P1 and P2, of the porcine Insulin-like Growth Factor 2 (IGF2) gene and to investigate the effect of IGF2 genotypes on meat quality traits in the Italian autochthonous Suino Nero Lucano pig. Three polymorphic sites were analysed and only two of the eight potential haplotypes were observed in the Suino Nero Lucano pig population: A haplotype (–366A – –225G – –182C), and B haplotype (–366G – –225C – –182T). Muscle mass and meat quality characteristics were analysed in 30 castrated pigs (10 for each of the three IGF2 genotypes: A/A, A/B, and B/B). According to the results, B/B animals, at the same carcass weight, showed the highest Longissimus lumborum and Psoas weight (P < 0.05), whereas A/A animals showed a higher intramuscular fat percentage and lower Warner–Bratzler shear force, drip loss, and polyunsaturated fatty acids content. Meat from B/B animals showed also a higher L* value and myoglobin and deoxymyoglobin percentage compared with meat from A/A ones (P < 0.05).