Steady shear (η) and complex viscosities (η*) are important rheological properties of honeys. In this study, the effects of temperature and total soluble solids (TSS) concentration on these properties in 40 different Brazilian honeys were investigated. All honeys showed liquid-like behaviour at the temperatures and mechanical spectra tested and, except for the orange blossom and multisoutheast samples, respected the Cox-Merz rule. It was found that η varied between 147.3 Pa s and 0.35 Pa s, and η* between 151.33 Pa s and 0.42 Pa s, at 10°C and 60°C, respectively. Four experimental models (Arrhenius, Williams-Landel-Ferry (WLF), Vogel-Tamman-Fulcher (VTF), and power law) were used to evaluate the effect of temperature on η and η*. The Arrhenius model was the most appropriate for estimation of η of all honeys and η* of some. WLF was the most appropriate for predicting η* of the orange blossom, multisoutheast, and multi-southern honeys. Increase in temperature and decrease in TSS concentration lowered these values. The effect of TSS concentration on η and η* at different temperatures could be appropriately described by the power law and exponential models. Simplified models were proposed to determine the η and η* from the combined effect of both factors, which presented R 2 of 0.9540 and 0.9334, and RMSE of 8.00 and 10.44, respectively. Thus, all models obtained in this study provide important tools towards the proper industrialisation of honeys and honey-based products.
We analyzed drip loss in pork by comparing the standard bag (DL), filter-paper wetness (FPW), and EZ-DripLoss methods by weighing the meat juice container and dabbed sample after 24 h and 48 h. Samples were classified into quality categories based on pH, color, and drip loss. The relationship between DL and FPW revealed the cut-off of 5% DL as corresponding to FPW of 139 mg; 1.89% when analyzed by weighing meat juice container or dabbed sample after 24 h; and 3.18% and 3.74% for those analyzed by weighing both meat juice container and dabbed sample after 48 h, respectively. Highest correlations were observed between DL and EZ when the meat juice container was weighed after 48 h (r=0.86). The EZ-DripLoss method in which the meat juice container was weighed after 24 h was able to distinguish drip loss into meat-quality categories in accordance with the bag method. Therefore, this method is recommended for meat categorization because of its greater standardization and ease of application.
The objective of this study was to evaluate the effect of freezing prior to wet aging on the color of Nellore and Aberdeen Angus cattle meat. Samples of the Longissimus thoracis muscle were subjected to two treatments: conventional aging (0, 7, 14 and 21days); and freezing (-20°C for 40days) followed by thawing and aging. Freezing promoted (P<0.05) formation of metmyoglobin during aging, especially in Nellore beef. Frozen meats showed (P<0.05) lower lightness (L*) values and higher redness (a*), chroma (C*) and hue angle (h*) values at the first day of storage, deteriorating quickly with aging time. The color of the Nellore meat was less (P<0.05) stable to freezing, being lighter, yellower and less red than Angus meat. The results suggest that color stability in vacuum-packed beef is reduced by freezing prior to aging and that reduction depends on the animal breed.
The effects of washing solutions and number of cycles on mechanically deboned turkey meat (MDTM) were evaluated for the production of surimi‐like material (SLM) using water, sodium chloride, sodium bicarbonate, and potassium phosphate buffer. Yields vary from a low of 30.98% with sodium chloride solution to as high as 37.33% with sodium bicarbonate. Chemical composition of washed samples showed moisture content of 75.46%–79.52%, fat at 5.87%–7.14%, protein at 12.35%–15.36%, and ash at 0.81%–1.29%. Repeated washings resulted in reduce in soluble proteins. Washing with sodium bicarbonate increased sodium content of unwashed MDTM from 60.76 mg/100 g to 109.41 mg/100 g, while water and phosphate buffer decreased it to 5.33 mg/100 g and 7.95 mg/100 g. SLM washed with sodium bicarbonate had higher pH and water holding capacity, and showed better changes in color characteristics than unwashed MDTM and other SLMs. This study demonstrates that sodium bicarbonate solution provided a desirable SLM with best technological quality.
Practical applications
MDTM is widely used by the Brazilian industry in the production of meat products, in which the use of up to 60% of the product is allowed. However, in products with a low fat content and with light color characteristics, such as some cured cooked poultry, the use of MDTM is limited precisely because it contains high content of fats and heme pigments. Washing process is one of a practical method to produce SLM resulting in higher myofibrillar proteins concentration and lower fat and heme pigments. However, different washing solutions and multiple washes provide different qualities of SLM from different species. Thus, determining the optimal washing process and its effects on the SLM characteristics is important for its application in meat products with low fat and with less pigmentation. Due to its properties, all types of SLM had potential applications for meat replacer in the production of emulsified and restructured meat products, with emphasis on the SLM obtained by use of sodium bicarbonate washing solution.
The rheological and thermal properties of honeys have a practical importance for beekeepers and industries, as their determination allows their proper processing and quality control. However, few studies have been carried out in this area with Brazilian honeys. Therefore, physicochemical, rheological and thermal properties of 40 Brazilian honeys of different floral origins were determined in this study. All the physicochemical properties indicated that the analyzed honey samples met the criteria for honeys established by Codex Alimentarius. The honeys showed non‐Newtonian behavior from 10C to 15C and Newtonian behavior from 20C to 30C with the influence of temperature on viscosity and on the viscous modulus (G″) described by the Arrhenius models. Oscillatory rheological data revealed a liquid‐like behavior (G″> elastic modulus (G′)) of the honeys. The glass transition temperature (Tg) of the honeys varied between −46.7C and −43.7C. By the principal component analysis (PCA), the first component explained 70.0% of the variation of the data, forming two groups described by moisture content, aw, viscosity (10C to 30C), G″ and Tg. This analysis confirms the important influence of the moisture content and of aw in the rheological and thermal properties of honeys and provide useful information for the industrialization of honey and honey‐based products.
Practical Application
Determining the honey rheological and thermal properties allows its proper processing and quality control, preventing the waste of economic resources. Conclusions for beekeepers and industries are: the honey physicochemical properties are in conformity with the Brazilian legislation and the Codex Alimentarius, which could be used by consumers and the food industry; rheological and thermal properties are inversely correlated with the moisture content and with aw, and could be used to distinguish Brazilian honeys; Brazilian honeys behave as diluted materials, and their viscosity is temperature‐ and floral origin‐dependent. Determining their viscosity helps in the performance, sizing and selection of equipment such as pumps, mixers, filters, centrifuges and heat exchangers; temperature fluctuations induce physical and chemical alterations in the honey, and temperature control during its processing and storage is important for maintaining its quality. All of these parameters provide useful information for the development of new products, optimization of industrial processes and control of quality and authenticity of honeys.
Pork may be classified into quality categories according to its color, texture and exudation, though no international consensus criterion has been reached yet. Thus, the aim of the present paper was to examine the relation between important meat quality traits
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