José M. Lorenzo

Influence of natural extracts on the shelf life of modified atmosphere-packaged pork patties

In this study four natural extracts from tea (TEA), grape (GRA), chestnut (CHE) and seaweed (SEA) with potential antioxidant activity were evaluated in pork patties. During 20 days of storage in modified atmosphere packs at 2°C, pH, colour, lipid oxidation and microbial spoilage parameters of raw minced porcine patties were examined and compared with a synthetic antioxidant (BHT) and control (CON) batch. Due to their higher polyphenol content, GRA and TEA extracts were the most effective antioxidants against lipid oxidation, also limiting colour deterioration. In addition, both natural extracts led to a decrease of total viable counts (TVC), lactic acid bacteria (LAB), Pseudomonas and psychotropic aerobic bacteria compared to the control. Among the four natural compounds tested, tea and grape extracts showed the most potential as alternatives to commercial antioxidants, for increasing the quality and extending the shelf-life of porcine patties.

Carcass characteristics, meat quality and nutritional value of horsemeat: A review

Meat has exerted a crucial role in human evolution and is an important component of a healthy and well balanced diet due to its nutritional richness. The aim of the present review was to shed light on the nutritional composition of horsemeat and their benefits for human health. One of the reasons for such interest was the occurrence, in Europe several years ago, of dioxin, Bovine Encephalopathy and foot-and-mouth disease problems in farm animals. Therefore, consumers began to look for alternative red meats from other non-traditional species. There is no carcass classification system on horses designated to meat consumption. It would be advisable to standardize the equine meat market to reduce variations that may reflect differences in meat quality. The nutritional composition of horsemeat by comparison with pork, beef or poultry is characterized by low levels of fat and cholesterol (about 20% less), relatively high concentrations of n-3 fatty acids and heme iron indicating that its consumption may be beneficial for health. Therefore, horsemeat may supplement the meat market with good quality products, although as in other dietary components moderation is advisable.

Effect of different cooking methods on lipid oxidation and formation of volatile compounds in foal meat.

The influence of four different cooking methods (roasting, grilling, microwaving and frying) on cooking loss, lipid oxidation and volatile profile of foal meat was studied. Cooking loss were significantly (P<0.001) affected by thermal treatment, being higher (32.5%) after microwaving and lower after grilling (22.5%) and frying (23.8%). As expected, all the cooking methods increased TBARs content, since high temperature during cooking causes increased oxidation in foal steaks, this increase was significantly (P<0.001) higher when foal steaks were microwaved or roasted. The four different cooking methods led to increased total volatile compounds (between 366.7 and 633.1AU×10(6)/g dry matter) compared to raw steaks (216.4AU×10(6)/g dry matter). The roasted steaks showed the highest volatile content, indicating that increased cooking temperature increases the formation of volatile compounds. Aldehydes were the most abundant compounds in cooked samples, with amounts of 217.2, 364.5, 283.5 and 409.1AU×10(6)/g dry matter in grilled, microwaved, fried and roasted samples, respectively, whereas esters were the most abundant compounds in raw samples, with mean amounts of 98.8AU×10(6)/g dry matter.

Fat effect on physico-chemical, microbial and textural changes through the manufactured of dry-cured foal sausage Lipolysis, proteolysis and sensory properties

The effect of fat content on chemical traits related to dry-curing process (pH, moisture and water activity), color and textural properties and changes of free fatty acids and amino acids compositions during the processing of foal dry-cured sausages were studied. For this purpose, three batches (20 units per batch) of dry fermented sausages with different pork back fat content (5%, 10% and 20%) were manufactured; low fat (LF), medium fat (MF) and high fat (HF), respectively. Samples at 0 days (mix before stuffing), and after 7, 14, 28, 42 and 49 days of ripening were taken. The fat level affected color and textural parameters at the end of the process, showing dry-cured foal sausage with the higher level of fat, the highest values of luminosity and the least hardness. No significant differences (P>0.05) among batches were detected on total viable counts, lactic acid bacteria and Microccaceae during the process. Regarding lipolysis and lipid oxidation it can be deduced that the increase in the fat level encouraged the production of free fatty acids and 2-thiobarbituric acid reactive substances. At the end of the ripening individual free fatty acids followed this order: oleic, palmitic, linoleic and stearic acid, representing 82-95% of the total free fatty acids. Final level of TBARS index was in the worst case of 1.23 mg MDA/kg of sausage. On the contrary, the batch with lesser fat content showed the highest levels of free amino acids at the beginning and at the end of the process, showing final values of 1.6%.

Effect of addition of green tea, chestnut and grape extract on the shelf-life of pig liver pâté

The effect of the addition of natural antioxidants (tea, chestnut and grape seed extracts) on physico-chemical and oxidative stability of refrigerated stored pig pâtés was studied. This effect was compared with that showed by the synthetic antioxidant BHT. Pâté samples were analysed at 0, 4, 8 and 24 weeks of refrigerated storage (4°C). Colour parameters were affected by storage period and antioxidant extract. Samples with CHE and GRA extracts showed lower total colour difference between 0 and 24 weeks. The amount of TBARS gradually increased during refrigerated storage with the exception of pâtés that have CHE extract in composition. At the sampling end point, the lower TBARS values were obtained in samples with TEA and GRA extracts. Finally, the evolution of volatile compounds during storage showed an increase in the lipid-derived volatile values after refrigerated storage, since samples with TEA and GRA extract showed the lowest values.

Biogenic amine content during the manufacture of dry-cured lacón, a spanish traditional meat product : Effect of some additives

The content of nine biogenic amines (agmatine, tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine) was determined throughout the manufacture of dry-cured lacón, a traditional dry-salted and ripened meat product made in the north-west of Spain from the fore leg of the pig following a similar process to that of dry-cured ham. The effect of the use of additives (glucose, sodium nitrite, sodium nitrate, sodium ascorbate and sodium citrate) on the biogenic amine content during manufacture was also studied. Tryptamine and spermine were the main biogenic amines in fresh meat, while tryptamine and cadaverine were the most abundant at the end of the manufacturing process. During ripening the total amine content increased significantly (P<0.05) in the batches made both without and with additives. The use of additives significantly (P<0.05) increased the total amine content and the content of tryptamine, tyramine and histamine. The total biogenic amine content at the end of the manufacturing process was low as expected for a product in which there is little active microbial metabolism during manufacture.

Proteolytic and lipolytic modifications during the manufacture of dry-cured lacón, a Spanish traditional meat product: Effect of some additives

The extractability of sarcoplasmic and myofibrillar proteins, the myofibrillar proteins and their degradation products, classical nitrogen fractions, free amino acids, acidity of the fat, and free fatty acids were determined throughout the manufacturing process of dry-cured lacón, a traditional dry-salted and ripened meat product made in the northwest of Spain from the foreleg of the pig, following a similar technological process to that of dry-cured ham. The effect of the use of additives (glucose, sodium nitrite, sodium nitrate, sodium ascorbate and sodium citrate) on the proteolytic and lipolytic changes was also studied. Throughout the manufacture, approximately 87% of the sarcoplasmic proteins and 91% of the myofibrillar proteins became insoluble. There was a significant (p<0.05) decrease of the myosin heavy chain, actin, and myosin light chains 1, 2 and 3, and also a significant (p<0.05) increase in the components generated as a result of the degradation of these myofibrillar proteins. The content of the different nitrogen fractions and of the free amino acids indicated that protein degradation during the manufacture of dry-cured lacón is only moderate. Data on the acidity of fat and of free fatty acids also indicated that lipolysis in dry-cured lacón is lower than in hams. The use of additives did not significantly influence the protein and lipid degradation, which occur throughout the manufacturing process.

Effect of cross breeding and amount of finishing diet on growth parameters, carcass and meat composition of foals slaughtered at 15 months of age.

This trial was conducted to study the effects of cross breeding (GM: Galician Mountain; HB×GM: Hispano-Breton×Galician Mountain crossing) and finishing feed (1.5 kg vs. 3.0 kg of commercial feed in the finishing period) on growth, performance, carcass characteristics and meat quality of foals slaughtered at 15 months of age. For this study, twenty one foals of GM and HB×GM crossbred were used. Results obtained for the current study suggest an interesting potential for meat production, because the introduction of HB×GM stallions allows an advantage compared with the Galician breed, because they had better carcass weight, better conformation and the best carcass ratios. Other morphometric measurements related to the leg were also higher in HB×GM crossbred. On the other hand, the finishing diet had also significant influence in commercial cuts both in the front and hind quarter. A finishing diet with 3 kg of commercial feed increased carcass fat level. Regarding meat quality, genotype did not affect any physical-chemical trait, while finishing foals with 3 kg of fodder quadrupled intramuscular fat value and provided meat with a higher luminosity (35.9 vs. 38.2, P<0.05, for 1.5 and 3 kg concentrate/day, respectively). However, this increase in intramuscular fat was not correlated with improvements in meat textural parameters because they were not influenced (P>0.05) by either of the two effects studied. Nutritive profiles (both fatty and amino acids composition) were not influenced by genotype (P>0.05) whereas finishing effect modified almost all fatty acid finding.

Influence of type of muscles on nutritional value of foal meat.

The effect of type of muscle on nutritional characteristic (fatty acid profile, amino acid content, cholesterol and major and minor mineral) of foal meat was investigated. Six muscles: longissimus dorsi (LD), semimembranosus (SM), semitendinosus (ST), biceps femoris (BF), triceps brachii (TB) and psoas major & minor (PM) from twelve foals slaughtered at 15 months from an extensive production system in freedom regimen were extracted for this study. Horse meat is characterized by low fat, low cholesterol content, rich in iron and in vitamin B. Statistical analysis showed that the cholesterol content did not show significant differences (P>0.05) among muscle with mean value range between 0.62 and 0.57 mg/100g. Most fatty acid presented significant differences (P<0.05) with respect to the type of muscle. The obtained results showed that except for the polyunsaturated linoleic acid, the highest contents of fatty acids were found in the hindquarter muscles. Regarding amino acid profile, significant differences (P<0.05) were observed among muscles and our results indicated that, 100g of foal meat covered from 80.6 to 86.7% for the daily requirement for an adult man weighing 70 kg for essential amino acids for ST and LD muscles, respectively. Statistical analysis showed significant differences (P=0.050) for the EAA (essential amino acids) index, which was highest for TB muscle, followed by BF and SM muscles, while the lowest values were reported by ST muscle. Finally, foal meat seems to be a very good nutritional source of major and minor minerals. The higher nutritional value of foal meat will be of great importance in the promotion of this meat.

Effect of pork fat addition on the volatile compounds of foal dry-cured sausage

The effect of fat content on volatile compounds from foal dry-cured sausage was studied. Three batches (10 units per batch) of dry fermented sausages with different pork back fat content (5%, 10% and 20%) were manufactured; low fat (LF), medium fat (MF) and high fat (HF), respectively. A total of 45 volatile compounds were extracted by purge-and-trap and identified by GC-MS in the headspace of the batches. The mixture comprised 11 terpenes, 15 esters, 14 hydrocarbons and 2 alcohols. Spices were responsible for the generation of 14 volatile compounds comprising terpenes and hydrocarbons. After 49 days of ripening volatile compounds from spices represented 52.9, 38.9 and 31.2% of the total area for samples from LF, MF and HF batches, respectively, while lipid autooxidation was responsible for the generation of 8 volatile compounds. The PCA offered a good separation of the mean samples according to their fat content.