Agnieszka Wierzbicka

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 packaging method and cold-storage time on chicken meat quality

This study was performed to determine the effects of vacuum packaging (VP) and modified-atmosphere packaging (MAP) (CO2/N2 = 3:7) on the physicochemical properties and sensory attributes in chicken breast meat during storage at 2ºC±0.5ºC for 5, 10 and 15 days. Results showed that storage time influenced the physicochemical properties, except sensory attributes, shear force and shear energy of chicken meat. The extended storage time was causing an increase in the pH value, drip loss and in values of color parameters (L, a* b*) in chicken meat. Moreover, the packaging method affected values of drip loss, cooking loss and shear force. Fresh meat (0 days of storage) was characterized by the highest overall quality assessed with the semi-consumer scaling method. Storage time and packaging method were found to exert significant effects on the physicochemical parameters determined instrumentally and on sensory attributes of meat evaluated with the semi-consumer scaling method.

Influence of the wheat flour extraction degree in the quality of bread made with high proportions of β-glucan

β-glucan is currently one of the most important bioactive substances. Hence, there is a growing interest in the production of various foods containing β-glucan. The study examines the influence of the degree of wheat flour extraction in the quality of breads with high β-glucan content. Rheological tests were conducted on dough. Volume, mass, color and texture of bread were measured after baking. We observed that increasing the degree of extraction caused an increase in the storage and loss modulus. All of the bread made from the different flours were smaller in volume after the addition of β-glucan, although the yield increased. The crumb color of β-glucan-added breads was darker than the control samples. Control samples were higher in textural parameters (firmness, gumminess and chewiness). β-glucan-added samples had decreased porosity. The results revealed that using very strong flour with a high protein content results in a high quality β-glucan bread with a higher nutritional value due to the high total dietary fiber and β-glucan content.

Carbon monoxide concentration and exposure time effects on the depth of CO penetration and surface color of raw and cooked beef longissimus lumborum steaks.

This study investigated the influence of carbon monoxide (CO) exposure time (0, 7, 14, and 21days) and concentration in gas mixture on depth of penetration and the surface color of raw and cooked striploin steaks. Seven packaging treatments were evaluated: vacuum, vacuum after 48h of exposure to 0.1%, 0.3% or 0.5% CO (mixed with 30% CO2 and 69.5-69.9% N2), and modified atmosphere packaging (MAP) containing the same gas mixtures. CO penetration depth increased as exposure times and CO concentration in gas mixtures increased (p<0.05). However, the carboxymyoglobin that formed did not always turn brown during thermal treatment. In cooked samples treated with 0.3% and 0.5% CO-MAP, a red carboxymyoglobin border was visible at the cross section, whereas other CO packaging treatments had its partial or total browning. To create a red color in raw and avoid a red boarder in cooked beef, up to 0.5% CO in vacuum packages and only 0.1% for MAP can be recommended.

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.

Applications of electronic noses in meat analysis

Electronic noses are devices able to characterize and differentiate the aroma profiles of various food, especially meat and meat products. During recent years e-noses have been widely used in food analysis and proved to provide a fast, simple, non-expensive and non-destructive method of food assessment and quality control. The aim of this study is to summarize the most important features of this analytic tool and to present basic fields and typical areas of e-nose use as well as most commonly used sensor types and patterns for e-nose design. Prospects for the future development of this technique are presented. Methods and research results presented in this manuscript may be a guideline for practical e-nose use.

Combined use of cocoa dietary fibre and steviol glycosides in low-calorie muffins production

Summary Today, consumers are more conscious about nutrition and food products with health benefits. In this study, partial sucrose replacement (20%) with steviol glycosides derived from Stevia Rebaudiana and total replacement of cocoa powder with cocoa fibre preparation in muffins were conducted. There were three levels of dietary fibre addition – 3%, 6% and 12%. Physical analysis of texture, colour, cooking yield and porosity was conducted. Moreover, chemical analysis of total dietary fibre and total phenol content was made as well. Sensory evaluation in two parts was also carried out. The experiment revealed the increase in firmness, porosity, TDF and TCP and the decrease in springiness, cohesiveness and lightness. The best-ranked sample in sensory evaluation was muffin with 6% of TDF sweetened with mixture of sugar and stevia. Stevia addition enhanced cocoa and sweet taste in tested muffins.

Effect of β-glucan particle size on the properties of fortified wheat rolls

The effects of β-glucan particle size and the ratios of β-glucan to flour on the physicochemical properties of wheat rolls were examined. A total of 100, 195 and 280 µm particles were analyzed with flour replacement from 0% to 20%. Wheat rolls made with the various particles and flour replacement levels were measured for rheology, yield and volume, texture, color, porosity, total dietary fiber (TDF) content and β-glucan content. All products had a smaller volume compared to the control, whereas the lightness was not significantly affected. Texture analysis indicated that the most favorable textural values were observed for the formulation involving the 195 μm β-glucan particles. Rolls with the same flour replacement level using the smaller particles had a higher share of TDF due to the greater surface of water evaporation. The main finding from the research was that the best results in most measured parameters were observed using 195 µm dietary fiber preparation. Thus, particle size reduction might be used to improve product properties but only to a certain extent because the load of micronized fiber weakens the structure, resulting in decreased product quality.

Effect of oat β-glucan fiber powder and vacuum-drying on cooking quality and physical properties of pasta

Oat β-glucan fiber powder was added to pasta dough at levels of 40, 80, 120, 160, and 200 g/kg. Pasta was dried at very high temperature and in a vacuum dryer. The cooking quality was evaluated based on the swelling index, water uptake, and cooking loss measurement. Further tests were carried out to determine the color, hardness, adhesiveness, total dietary fiber (TDF), and β-glucan content in pasta. The results showed that vacuum-drying had a significant impact on the cooking quality and physical properties of pasta. Water uptake and swelling index were higher and the cooking loss was lower in vacuum-dried pasta than in pasta dried using very high temperature (VHT) technology. The swelling index, water uptake, and cooking loss were significantly higher in samples with oat β-glucan fiber powder compared to control. Pasta with oat powder was darker, softer, and less sticky than semolina pasta. Lightness of vacuum-dried samples was higher while redness was lower than in conventionally dried samples.