G. Grigioni

Warmed-over flavour analysis in low temperature–long time processed meat by an “electronic nose”

The ability of an electronic nose, comprising 32 conducting polymer sensors, to identify and classify warmed-over flavour (WOF) aroma in bovine semitendinosus muscle, processed by vacuum cook-in-bag/tray technology (VCT) and storage under refrigerated conditions, was evaluated. The VCT process employed low temperature-long time (50°C-390 min) thermal treatments. Multivariate analysis showed that VCT processed beef aroma profiles were sorted into two groups, one included samples stored for up to 20 days and the other included samples with 34 to 45 days of storage. WOF odour standard samples were recognised to have similar aroma as samples of the second group. Lipid oxidation results, measured by thiobarbituric acid reactive substances, showed an increment in oxidation level for samples stored for 34 days or more (P<0.05). This study shows that electronic nose technology can be applied to WOF odour identification and classification in VCT beef meat, complementing chemical and sensory techniques used in this field.

Effect of whey protein concentrate and sodium chloride addition plus tumbling procedures on technological parameters, physical properties and visual appearance of sous vide cooked beef

Beef muscles cooked by the sous vide system were evaluated for the effects of pre-injection tumbling, brine addition and post-injection tumbling on technological parameters, physical properties, visual appearance and tissue microstructure. The muscles were injected at 120% (over original weight) with a brine formulated to give a concentration of 3.5% whey protein concentrate and 0.7% sodium chloride on an injected raw product basis. Pre-injection tumbling did not affect most of the evaluated parameters. Brine addition reduced significantly the cooking and total weight losses. Total weight loss was 7.2% for injected muscles, and significantly higher (28.2%) for non-injected ones. Brine incorporation increased pH and reduced shear force values of cooked muscles. Extended post-injection tumbling (5rpm-10h) improved brine distribution and visual appearance, and also diminished the shear force values of cooked muscles. However, this treatment increased the weight losses of post-injection tumbling and cooking-pasteurization stages.

Diet and genotype effects on the quality index of beef produced in the Argentine Pampeana region.

Steers of varying genotypes (Aberdeen Angus, Charolais x AA and Argentine Holstein) in four feeding systems were evaluated. Feeding systems were: S1=a diet based on pastures only; S2=a similar forage base as S1 plus a daily supplementation with cracked corn, at 0.7% of l.w./head/day; S3=a similar forage base as S1 plus a daily supplementation with cracked corn, at 1.0% of l.w./head/day; and S4=a regular feedlot diet. Tenderness and marbling were not affected by the feeding system. Feedlot meat showed an n-6/n-3 ratio significantly higher than meat produced with the diets based on pastures (S1=2.1; S2=3.1; S3=4.5; S4=14.2) (P<0.05), whereas CLA content had an inverse behavior, showing S1 (0.67%) and S2 (0.64%) higher concentrations than S3 (0.55%) and S4 (0.28%) (P<0.05). Diet based on pastures plus a low level of supplementation produced meat with better nutritional characteristics than other productive alternatives, without significant effects of the biotypes.

Antioxidant consumption and development of oxidation during ageing of buffalo meat produced in Argentina.

Buffalo meat production is increasing in Argentina. Information on meat quality and nutritional value will be useful in marketing. This work describes the oxidative stability of the Longissimus dorsi (LD) in relation to consumption of antioxidant vitamins, fatty acid composition and color deterioration during ageing. Vitamins levels found in fresh beef were 4.22±0.93; 0.24±0.05 and 0.25±0.06μg/g for α- and γ-tocopherol, and β-carotene, respectively. Vitamin loss was almost 90% throughout an ageing period of 25 days at 2°C. Concomitantly, TBARS levels increased from 0.076±0.018 to 0.14 6±0.032mg MDA/kg beef. Hexanal and pentanal levels were low and no correlations with oxidation were detected (P>0.05). The predominant color changes in aged beef were reduced redness and yellowness with an increase in lightness (P<0.05). Vitamin levels and TBARS were used to develop a prediction equation for post-mortem aging.

Effect of aging on the characteristics of meat from water buffalo grown in the Delta del Paraná region of Argentina.

Fifteen crossbreed water buffalos were selected from a farm in Delta del Paraná, Entre Ríos Province, Argentina. Animals were castrated males 20-24 months old reaching final live weights of 400-420kg. They were predominantly of Mediterranean and Murrah breeds and were feed in naturally grown pastures. Tenderness and chewiness increased with postmortem aging (p<0.05). Aging did not affect flavour and odour scores, even though certain off-flavours and off-odours were reported. Changes in colour with aging were similar to those seen in beef.

Tomato Quality during Short-Term Storage Assessed by Colour and Electronic Nose

An assay based on an electronic olfactory system was set to evaluate tomato fruits by sensing the aromatic volatiles during postharvest storage of 21 days at 19±0.5∘C in darkness. Olfactory system measurements were coupled with colour values. Odour profile and senescence parameters were carried out at 7-day intervals. Discriminant function analysis applied to electronic nose data showed three components, accounting for 99.2% of the total variance. In the present assay, separation among groups according to storage time (0, 7, and 14 days) was observed for wildtype. Overexpressed (Money Maker) lines/plants of tomato showed difference between odour profile for day 0 and day 21, even tough a no clear discrimination between 7 and 14 days was observed. Fruit lost weight almost linearly with shelf life (𝑃<0.001) presenting an averaged loss of 21% (𝑟2=0.98) for over-expressed (Money Maker) lines/plants, 13% (𝑟2=0.97) for silenced (Money Maker), and 14% (𝑟2=0.98) for wild type during 21 days of storage. Colour values 𝐿∗, 𝑎∗, and 𝑏∗ data showed that colour properties changed during storage for all the lines considered. Correlations between odour profiles and colour parameter were obtained showing that the electronic nose is a useful technique for monitoring short-term storage of tomato.

Effect of feeding treatment during the backgrounding phase of beef production from pasture on: I. Animal performance, carcass and meat quality.

This research evaluated effects of feedlot backgrounding on 40, 70 or 100% alfalfa hay diets (40 hay, 70 hay; 100 hay, respectively) or pasture grazing (Pasture) before pasture finishing, on performance and beef characteristics of Angus heifers. Ninety six female calves were allocated to the four feeding strategies. Backgrounding took place during 114 days and subsequent pasture finishing over 132 days. Heifers of each strategy were slaughtered after 114 days (end of the feedlot period) and at end of the study when all remaining animals were finished on pasture. Effects of backgrounding were associated with rate of gain. Backgrounding strategies 40 hay and Pasture resulted in the best performance. Beef attributes were similar. At the end of the feedlot period, 100 hay was smaller and leaner, less tender and less juicy. At the end of the study, Pasture and 40 hay heifers had on average the largest back fat thickness and intramuscular fat measurements. No treatment effects were detected for Warner-Bratzler shear force, muscle pH, muscle color and sensory panel attributes.

Effect of the addition of conventional additives and whey proteins concentrates on technological parameters, physicochemical properties, microstructure and sensory attributes of sous vide cooked beef muscles.

Beef muscles submitted to four enhancement treatments (1.88% whey protein concentrate (WPC)+1.25% sodium chloride (NaCl); 1.88% modified whey protein concentrate (MWPC)+1.25%NaCl; 0.25% sodium tripolyphosphate (STPP)+1.25%NaCl; 1.25%NaCl) and a control treatment (non-injected muscles) were sous vide cooked. Muscles with STPP+NaCl presented a significantly higher total yield (106.5%) in comparison to those with WPC/MWPC+NaCl (94.7% and 92.9%, respectively), NaCl alone (84.8%) or controls (72.1%). Muscles with STPP+NaCl presented significantly lower shear force values than control ones; also, WPC/MWPC+NaCl added muscles presented similar values than those from the other treatments. After cooking, muscles with STPP+NaCl or WPC/MWPC+NaCl depicted compacted and uniform microstructures. Muscles with STPP+NaCl showed a pink colour, meanwhile other treatment muscles presented colours between pinkish-grey and grey-brown. STPP+NaCl added samples presented the highest values of global tenderness and juiciness. The addition of STPP+NaCl had a better performance than WPC/MWPC+NaCl. However, the addition of WPC/MWPC+NaCl improved total yield in comparison to NaCl added or control ones.

Meat quality traits of commercial hybrid pigs in Argentina.

This report describes the meat quality of two INTA hybrids (hybrid females) sired by Duroc (D) or Yorkshire (Y) boars and a third one from PIC (S), a cross of females C22 to 412 boars. Starting at 30kg live weight, 18 barrows and 18 gilts of each genotype were kept in identical conditions until slaughtered at 110kg. Longissimus dorsi muscles were analyzed. Means differed significantly (P<0.05) for drip loss (higher in S); tenderness (more tender in D), water holding capacity (higher in Y); cooking loss (higher in Y); colour parameter L(∗) (lower in D) and b(∗) (higher in S) and intramuscular fat content (higher in D). As a result of sensory analysis, it was found that D was the most tender and juicy. There were few sex effects and no genotype-sex interactions. Distinct differences in meat quality between hybrids do exist, with D superior, S the worst, and Y intermediate.

A Contribution of Beef to Human Health: A Review of the Role of the Animal Production Systems.

Meat and meat products constitute important source of protein, fat, and several functional compounds. Although beef consumption may implicate possible negative impacts on human health, its consumption can also contribute to human health. Quality traits of beef, as well as its nutritional properties, depend on animal genetics, feeding, livestock practices, and post mortem procedures. Available data show that emerging beef production systems are able to improve both, quality and nutritional traits of beef in a sustainable way. In this context, Argentinas actions are aimed at maximising beef beneficial effects and minimising its negative impact on human health, in a way of contributing to global food security.