Andrzej Półtorak

ANALYSIS OF RELATIONSHIP BETWEEN BASIC COMPOSITION, pH, AND PHYSICAL PROPERTIES OF SELECTED BOVINE MUSCLES

Abstract The aim of this study was to analyse the correlation between basic meat composition (water, protein, fat, and connective tissue contents), pH value, and physical parameters (texture and colour, drip loss) of selected beef muscles. Five different muscles (LTH, SEM, SET, PSM, TRI) from 20 carcasses were examined. Measurements of the basic meat composition were conducted using a near infrared spectrometry method, colour parameters in L*a*b system, and texture parameters. Drip loss correlated strongly negatively with the pH value. Depending on the muscle type, the correlation ranged -0.601≤r≤-0.282, whereas drip loss correlated moderately positively with connective tissue content. The most significant positive correlation (r≈0.67) between hardness, tenderness, and fat content was noted in the SEM. Colour parameters strongly depended on pH values (-0.831≤rL*≤-0.338; - 0.828≤ra*≤-0.542; -0.912≤rb*≤-0.719) and to a lesser extent on the content of connective tissue.

Influence of 21 days of vacuum-aging on color, bloom development, and WBSF of beef semimembranosus

Changes of color, proportions of myoglobin forms, pH, Warner-Bratzler shear force (WBSF) of beef m. semimembranosus (SM) were examined during 21days of vacuum-aging. Significant changes in lightness, redness, yellowness, chroma, and hue angle (p≤0.05) of SM during aging were found. Proportions of myoglobin forms changed on the 7th day of aging. Aging decreased WBSF in general, but a significant decrease (p≤0.05) from 67.86N to 55.3N was observed after day 14 of aging. The color parameters (L*, a*, C, ΔE) and O2Mb in 21-day aged SM were stabilized faster during blooming. Beef SM that had faster stabilization of bright red color during blooming were more tender (correlation of O2Mb with WBSF r=-0.87; p≤0.001). This could be important information for the producers, since the best quality traits could be achieved after sufficient blooming and aging time.

Effect of MAP, vacuum skin-pack and combined packaging methods on physicochemical properties of beef steaks stored up to 12days.

The physicochemical properties of M. longissimus lumborum steaks over 12days of storage at 2°C, and under three packaging conditions, were investigated: vacuum skin packaging (VSP); modified atmosphere packaging (MAP), and their combination with semi-permeable inner VSP film (VSP-MAP). Standard gas composition (80% O2/20% CO2) was used for MAP and VSP-MAP packaging. CIE L*a*b* color parameters of VSP-MAP samples were similar to those kept in MAP and significantly higher to those stored in VSP. Myoglobin oxidation was more evident in VSP-MAP and MAP samples than in VSP indicating increased oxidation processes. However, storage in MAP resulted in greater lipid oxidation compared both to VSP and VSP-MAP. No differences between treatments were observed in terms of Warner-Bratzler shear force values and drip loss. In general, these results suggest that the combination of VSP and MAP methods may be an efficient way to reduce negative quality changes typical for both systems used separately.

The effect of the packaging system and storage time on myofibrillar protein degradation and oxidation process in relation to beef tenderness

This study investigated the impact of packaging systems on the degradation and oxidation of beef proteins regarding beef tenderness of longissimus lumborum (LL) and biceps femoris (BF) muscles stored in vacuum skin packaging (VSP), a modified atmosphere with high oxygen concentration (MAP), and combined of these two methods (VSP+MAP). A significant decrease in the Warner-Bratzler shear force (WBSF) in VSP at D14 and D28 for LL was observed compared to BF. A significant effect of packaging system on troponin-T (Tn-T) and desmin degradation was shown (p≤0.001). A high concentration of oxygen in MAP and VSP+MAP affected protein oxidation, which was reflected in myosin oxidative cross-linking. An increase of WBSF values detected in steaks packed in VSP and VSP+MAP systems could be caused by the intensification of protein oxidation. Furthermore, BF was more susceptible to oxidation compared to LL. The VSP+MAP packaging system has resulted in the maintenance of a bright, red color, however has not improved the beef tenderness.

Effect of reduction of oxygen concentration in modified atmosphere packaging on bovine M. longissimus lumborum and M. gluteus medius quality traits

This paper reports the impact of modified atmosphere gas compositions with different concentrations of CO2/O2/N2 on physicochemical traits of beef steaks from M. longissimus lumborum and M. gluteus medius. Samples were stored at +2°C for 12days. The gas compositions were as follows: (i) 50% O2/20% CO2/30% N2 (MAP1), (ii) 65% O2/20% CO2/15% N2 (MAP2) and (iii) 80% O2/20% CO2 (MAP3). Packaging atmosphere did not affect CIEL*a*b* colour coordinates, which were affected by storage time and by muscle type. Lipid oxidation in M. longissimus lumborum was affected by packaging treatment; however packaging treatment×storage time interaction affected lipid oxidation significantly. Results showed that reduction of oxygen from the commercially used 80% to 50% does not negatively impact colour properties and state of myoglobin, but significantly lowers oxidative deterioration of M. longissimus lumborum at the end of storage.

Impact of the ageing process on the intensity of post mortem proteolysis and tenderness of beef from crossbreeds

Abstract The aim of the study was the evaluation of the effect of ageing on the extent of myofibrillar proteins degradation and tenderness of beef in different crossbreeds, BB × HF and SM × HF, from which the musculus semitendinosus was obtained. The pH value, basic composition of meat, and colour parameters were determined on the 3rd d post mortem. The Warner Bratzler shear force and the extent of protein degradation were evaluated in regard to the effect of ageing time. Meat of BB × HF crossbreed had a lower amount of intramuscular fat and higher protein content (P ≤ 0.05). The shear force decreased with ageing time in the case of both crossbreeds. However, the highest values were noted in SM × HF crossbreed on days 3 and 7 of ageing. The differences in proteolysis of myofibrillar proteins and polypeptides, determined by SDS-PAGE electrophoresis, were observed between crossbreeds and the ageing time. A significant decrease in desmin and increased levels of 49-46 kDa and 32-27 kDa polypeptides (products of proteolytic degradation) were observed with an increasing ageing time. In addition, the rate of increase in the amount of 32-27 kDa polypeptides was more significant in BB × HF crossbreed. The data obtained showed that tenderness and the extent of protein degradation are associated with ageing process and animals’ genotype.

Influence of post-mortem muscle glycogen content on the quality of beef during aging

Abstract Introduction: Glycolic changes which occur post-mortem have an impact on the physical and sensory features of beef, which in turn determine the successive processes and influence such beef quality traits as colour, tenderness, and cooling loss. The aim of this study was evaluation of the post-mortem changes in bovine meat during aging, quantitative analysis of glycogen and lactic acid, as well as examination of their impact on technological and sensory quality of selected muscles from Holstein-Friesian × Limousin breed carcasses. Material and Methods: The study included three muscles of different metabolic qualities and sarcomere length: m. semitendinosus, m. longissimus dorsi, and m. psoas major, collected from nine bull carcasses aged 24 ±2 months. Results: Significant correlations were found between the volume of cooling loss on individual days of aging and the pH value of muscle tissue, lactic acid and glycogen content, as well as beef lightness. However, no significant dependency between the volume of glycogen and the intensity of red and yellow colours was detected. Conclusion: The colorimetric analysis of glycogen and lactic acid can be an effective tool in predicting the quality of beef.

The impact of ozone on health-promoting, microbiological, and colour properties of Rubus ideaus raspberries

ABSTRACT The purpose of the study was to define the impact of ozonisation duration and concentration on selected chemical, physical, and microbiological properties of Rubus ideaus red-fruited raspberries of the Polka variety. Raspberry fruit was exposed to a stream of ozone in concentration of 0.3 and 0.9 mg/L over a period of 60 and 120 min. The scope of the study covered the measurements of titratable acidity, soluble solids concentration, and such health-promoting indicators as content of phenol compounds, flavonoids, anthocyanins and vitamins C, total antioxidant activity (TAA) on 0, 4th, and 8th day of storage. The ozone treated fruit had higher level of phenol compounds and demonstrated higher TAA compared to untreated raspberries. The use of ozone made it possible to curb the development of yeast and moulds on the surface of raspberries, in which the dosage of 0.9 mg/L and treatment time of 60 min proved most efficient.

Impact of ozonisation on pro-health properties and antioxidant capacity of ‘Honeoye’ strawberry fruit

ABSTRACT The objective of the research was to determine the impact of concentration and ozonisation time on the selected chemical properties and total antioxidant capacity of ‘Honeoye’ strawberries cultivar. Efficiency of gaseous ozone usage as a method of extending the fruit shelf life was proved. Strawberries were exposed to ozone stream with concentration of 0.3–1.2 mg/L, within 60, 120, 150 and 180 min. The scope of research included measurements of the titratable acidity, content of soluble solid substances and the following pro-health characteristics: the total antioxidant capacity, phenolic compounds content and vitamin C content. On the second, fourth and sixth day of storage, an assessment was carried out on the fruit mass changes. Statistically significant differences (p < 0.05) in the titratable acidity changes and soluble solids concentration were reported. The application of ozone allowed reduction of strawberries weight losses during storage without a negative impact on their pro-health properties.

Dynamic Colour Changes Depending on the Temperature Inside the Final Beef Product in a Process of Frying and Grilling

Abstract Four different beef muscles (PM, SM, LTL, TB) were examined. These muscles were fried or grilled. Each muscle was observed at various internal temperatures: 60°C, 65°C, 70°C, and 75°C. At each temperature level, a measurement of colour was taken using a Minolta Chroma Meter CR-400 in a L*a*b* system. The values of the parameters L*, a*, and b* were measured on a cross-section sample (two areas) after cutting perpendicular to the fibres at the middle of its height. Area I was located at the central part of the steak with a diameter of 2 cm. Area II was located at a distance of 1 cm from the edge of the steak. From the results obtained, the difference in colour values between areas was noted. The results indicated that area I was lighter and redder in comparison to area II. The values of parameters L* and a* recorded in the first area were higher in comparison with the values from the second region, indicating that the sample in the area I was lighter and redder than in the area II at the outside of the sample. There was a large variation in the colour of the two areas. It was observed that for all sampled fried muscles, the highest difference in lightness (ΔL*) between the two test areas was obtained at a heat treatment temperature of Ti= 65°C inside the sample. With grilling the highest value for overall difference in colour between areas was from samples heated to a final temperature of Ti=60 °C.