Effect of frozen and refrozen storage of beef and chicken meats on inoculated microorganisms and meat quality.

The objective of this study was to investigate the effects of repeated freeze-thaw cycles on microorganisms, amino acid composition profile, chemical composition, mineral concentrations, water mobility, and fat of beef and chicken meats. Pure cultures of specific fungi and bacteria were separately injected into the minced meat. Apart from Pseudomonas, the total count of microorganisms significantly increased (P < 0.05) during refreezing treatment with the increase of storage period in both beef and chicken meats. During freezing treatment, the total count of Staphylococcus aureus, spore forming bacteria, and lactic acid bacteria were meat-type dependent. In conclusion, freeze-thaw cycles increased the microbial counts and decreased the water holding capacity, amino acids, and mineral concentrations of beef and chicken meats.

Changes in the thermal stability and structure of myofibrillar protein from quick-frozen pork patties with different fat addition under freeze-thaw cycles.

Changes in thermal stability and structure of myofibrillar protein from pork patties with different fat addition (0%, 5%, 10%, 15% and 20%) under freeze-thaw (F-T) cycles were discussed. The results showed that the total sulfhydryl, reactive sulfhydryl, free amino group, α-helix and ß-sheet contents, fluorescence intensity (FI), and protein thermal stability (Tmax, ∆Htotal) of samples with the same fat content were significantly decreased, while the ß-turn and random-coil content and the maximum fluorescence emission wavelength (λmax) were significantly increased with increasing F-T cycles (P < 0.05). These changes in samples with 20% fat at the 5th F-T cycle were obvious and were verified by the decreases in ∆Htotal (26.1%), reactive sulfhydryl (16.1%), and FI (16.8%) compared with the patties without fat. Therefore, repeated F-T cycles could decline the thermal stability of protein, destroy the protein structure of patty, and the changes were positively correlated with fat content of patty.

Standardized Extraction Techniques for Meat Analysis with the Electronic Tongue: A Case Study of Poultry and Red Meat Adulteration.

The electronic tongue (e-tongue) is an advanced sensor-based device capable of detecting low concentration differences in solutions. It could have unparalleled advantages for meat quality control, but the challenges of standardized meat extraction methods represent a backdrop that has led to its scanty application in the meat industry. This study aimed to determine the optimal dilution level of meat extract for e-tongue evaluations and also to develop three standardized meat extraction methods. For practicality, the developed methods were applied to detect low levels of meat adulteration using beef and pork mixtures and turkey and chicken mixtures as case studies. Dilution factor of 1% w/v of liquid meat extract was determined to be the optimum for discriminating 1% w/w, 3% w/w, 5% w/w, 10% w/w, and 20% w/w chicken in turkey and pork in beef with linear discriminant analysis accuracies (LDA) of 78.13% (recognition) and 64.73% (validation). Even higher LDA accuracies of 89.62% (recognition) and 68.77% (validation) were achieved for discriminating 1% w/w, 3% w/w, 5% w/w, 10% w/w, and 20% w/w of pork in beef. Partial least square models could predict both sets of meat mixtures with good accuracies. Extraction by cooking was the best method for discriminating meat mixtures and can be applied for meat quality evaluations with the e-tongue.

Perceptions of nutritional value, sensory appeal, and price influencing customer intention to purchase frozen beef: Evidence from Indonesia.

The lack of public understanding of frozen meat encourages consumers to buy only fresh meat, which has caused imported frozen meat to remain unabsorbed by the market despite the growing demand for meat. This study aims to analyze consumer perceptions that affect the intention to purchase frozen meat, which is mediated by the attitude toward frozen meat. Several factors were tested: perceived nutritional content, perceived sensory appeal, and perceived price. The method used in this study is quantitative ̶ an online questionnaire collects data from 536 customers who are the buyers and decision-makers in buying meat in their household. Structural equation modeling (SEM) was used to analyze the data. The results of this study indicate that higher consumer perceptions of nutritional content, sensory appeal, and price lead to higher attitudes toward frozen meat and in turn, increase purchase intention.

Raman spectroscopic techniques for detecting structure and quality of frozen foods: principles and applications.

Frozen foods are among the most popular food products and the development of techniques for the rapid detection of their structures and quality is important for the frozen food industry. In the current review, the principles and applications of Raman spectroscopic techniques in detecting and evaluating the structure changes and quality of frozen foods are discussed and merits and drawbacks of each Raman type are presented. These techniques include dispersive, Fourier transform, spatially offset, micro Raman spectroscopies. Raman spectroscopy can assess the compositional, physicochemical, and sensory characteristics of the frozen foods without any pretreatment. It can also be applied to investigate the structural alterations of protein, lipid, water and other components. Further trends of developing the Raman spectroscopy in monitoring the frozen foods should focus on reducing overlapping signals, achieving real noninvasive detection, eliminating misclassification and quantification errors, establishing standardized Raman database, and controlling cost.

Effect of freeze-thaw cycles on the quality of quick-frozen pork patty with different fat content by consumer assessment and instrument-based detection.

The change in quality of quick-frozen patties containing different amounts of added fat (0%, 5%, 10%, 15%, and 20%) under different freeze-thaw (F-T) cycles (a F-T cycle was performed by freezing at -18 °C and thawing at 4 °C) was evaluated. The results showed that the a*-values of samples were significantly decreased, while L*-values, b*-values, thawing loss, and cooking loss were notably increased after 3 F-T cycles. Low-field nuclear magnetic resonance (LF-NMR) results showed that the water mobility of patties was enhanced. Textural properties (hardness, springiness, cohesiveness, and chewiness) of patties were significantly decreased after 5 F-T cycles (P < 0.05). Lipid and protein oxidation were aggravated with increasing fat content and number of F-T cycles, as confirmed by the increase in lipid peroxides, TBARS, and carbonyl content. Therefore, the results from instrument-based detection and consumer scores indicated that repeated F-T cycles accelerated the quality deterioration of quick-frozen pork patties, and rendered them unacceptable after 3 F-T cycles.

Effect of different thawing methods on the efficiency and quality attributes of frozen red radish.

BACKGROUND: The thawing process is regarded as an essential step before the consumption of frozen foods. This study aimed to evaluate the possibility of ultrasound thawing of frozen red radish and to explore the characteristics of ultrasound thawing. The influence of low-frequency ultrasound (LFU) on the thawing efficiency of frozen red radish cylinders in air and water mediums was investigated. The effects of different ways of thawing, including air thawing (AT), water thawing (WT), refrigeration thawing (RT), ultrasound-assisted water thawing (UWT), and microwave thawing (MT) on the thawing time and quality of radish samples was studied. RESULTS: The results showed that thawing time decreased remarkably in air and water mediums assisted by LFU. As the LFU power level increased, the thawing time decreased and the value of the drip loss increased. The firmness of thawed radish samples also decreased significantly compared with the fresh samples. Microwave thawing had the highest thawing rate, but the microstructure of MT radish samples was damaged severely, resulting in the highest drip loss, and the lowest firmness, and vitamin C content. In comparison with the AT, WT, and RT, a significant reduction in thawing time could be achieved for UWT (P < 0.05). Ultrasound-assisted water thawing exhibited the highest retention of color and vitamin C, and a lower destructive effect on the microstructure. CONCLUSION: The results showed that LFU could be used as an efficient method to facilitate the thawing process of frozen red radishes, and better preserve the color, vitamin C, and microstructure of the final product. © 2020 Society of Chemical Industry.

Avaliação do ponto de congelamento do leite cru por espectroscopia de infravermelho com transformada de Fourier como método de triagem / [Fourier Transform Infrared spectroscopy (FTIR) as a screening method for freezing point in raw milk]

O objetivo deste estudo foi investigar a interferência do teor de gordura do leite no ponto de congelamento (PC) obtido pelo infravermelho com transformada de Fourier (FTIR). Uma fração de leite cru foi desnatada, obtendo-se creme e leite desnatado. O leite integral e o desnatado foram adicionados com água (0%, 2%, 5%, 10%, 15% e 20%). O leite desnatado remanescente foi adicionado com creme (5%, 10%, 15%, 20%) e água (0%, 2%, 5%, 10%, 15% e 20%). As amostras foram analisadas para PC (crioscópio eletrônico e FTIR) e composição (FTIR). O PC medido por FTIR foi altamente correlacionado com o método do crioscópio eletrônico (acima de 98,5%) e, como esperado, a adição de água foi significativa (P≤0,001) ao aumentar o PC do leite em ambos os métodos. No entanto, o alto teor de gordura no leite cru resultou na redução do PC ao se utilizar o FTIR, enquanto o baixo teor de gordura resultou em aumento do PC (P≤0,001). Uma vez que a adição de água causou o efeito inverso do alto teor de gordura no PC medido por FTIR, é importante considerar o teor de gordura do leite para evitar interpretações erradas do PC quando se utiliza o método FTIR.(AU)

The objective of this study was to investigate the interference of milk fat content upon the Freezing Point (FP) obtained by Fourier-transform infrared (FTIR). A fraction of raw milk was skimmed, obtaining cream and skim milk. Whole and skim milk were added with water (0, 2, 5, 10, 15, and 20%). The remaining skim milk was added with cream (5, 10, 15, 20%) and water (0, 2, 5, 10, 15, and 20%). Samples were analyzed for FP (thermistor cryoscope and FTIR) and composition (FTIR). FP measured by FTIR was highly correlated with the thermistor cryoscope method (above 98.5%) and, as expected, water addition was significant (P≤0.001) upon increasing milk FP in both methods. However, high fat content in raw milk resulted in decreasing FP when using FTIR, while low fat content resulted in increased FP (P≤0.001). Since water addition caused the inverse effect of high fat on FP measured by FTIR, it is important to regard the fat content of milk to avoid misinterpretation of FP when using the FTIR method.(AU)

Changes in the physical properties of frozen cooked rice depending on thermal insulation levels of packaging during freeze-thaw.

Frozen cooked rice, a common commercially available product, has become the food of convenience in different parts of the world. Frozen foods that are well made in factories often experience quality deterioration due to temperature fluctuation during distribution. This study aimed to evaluate the impact of repeated freeze-thaw, which may occur during distribution, on the physical quality of frozen cooked rice. Additionally, the effect of the thermal insulation levels of the packaging on the quality change of frozen cooked rice as a result of repeated freeze-thaw was analyzed. The repeated freeze-thaw treatment of frozen cooked rice resulted in moisture loss, microstructure destruction, increase in hardness, increase in adhesiveness, decrease in the L* -value, increase in the a* -value, increase in the b* -value, and increase in the ΔE-value. In particular, the quality of frozen cooked rice quickly deteriorated in samples stored in packaging with low thermal insulation. On the contrary, the higher the thermal insulation of the packaging, the longer the changes in the physical properties of the frozen cooked rice were delayed. The findings of the present study show that the deterioration of quality induced by the repeated freeze-thaw treatment of frozen cooked rice could be suppressed by thermal insulated packaging. PRACTICAL APPLICATION: The present study indicates that thermal insulated packaging can be used for industrial packaging of frozen cooked rice, as it delays the quality deteriorating effects of repeated freeze-thaw. This can help maintain the quality of frozen cooked rice and improve consumer satisfaction despite temperature fluctuations during distribution.

Quality enhancement of frozen Nile tilapia fillets using rosemary and thyme oil / [Melhoria da qualidade de filetes de tilápia do Nilo congelados com óleo de alecrim e tomilho]

The food industry and the frozen fish sector in particular have benefitted greatly from advancements in food processing technologies. This study investigated the effect of adding natural antioxidants such as rosemary and thyme oil to frozen fillets of Nile tilapia (Oreochromis niloticus) in order to preserve their quality for consumers. Fillets were treated with rosemary and thyme at two concentrations (1% and 1.5%) and then were stored at 4°C. Samples were analyzed over 4 days for bacteriological (aerobic plate count, psychotropic count, and coliform count), chemical (determination of pH, thiobarbituric acid reactive substances-TBARS, and total volatile base nitrogen-TVB-N), and sensory quality examination (color, texture, and odor). Significant differences (P<0.05) were observed among different groups in terms of aerobic plate count, psychotropic count, and coliform count during the storage. Moreover, pH, TVB-N, and TBARS mean values in the treated groups were lower than those in the untreated group. The best sensory quality was obtained at the highest concentrations (1.5%) of thyme and rosemary oil.(AU)

A indústria de alimentos e o setor de peixes congelados, em particular, se beneficiaram dos avanços nas tecnologias de processamento de alimentos. Este estudo investigou o efeito da adição de antioxidantes naturais, como óleo de alecrim e tomilho, a filetes congelados de tilápia do Nilo (Oreochromis niloticus), a fim de preservar sua qualidade para os consumidores. Os filés foram tratados com alecrim e tomilho em duas concentrações (1% e 1,5%) e, em seguida, foram armazenados a 4°C. As amostras foram analisadas durante 4 dias para análises bacteriológicas (contagem de placas aeróbicas, psicotrópicas e coliformes), químicas (determinação do pH, substâncias reativas ao ácido tiobarbitúrico-TBARS e nitrogênio base volátil total-TVB-N) e exame da qualidade sensorial (cor, textura e odor). Diferenças significativas (P<0,05) foram observadas entre os diferentes grupos na contagem aeróbia de placas, contagem psicotrópica e contagem de coliformes durante o armazenamento. Além disso, os valores médios de pH, TVB-N e TBARS nos grupos tratados foram inferiores aos do grupo não tratado. A melhor qualidade sensorial foi obtida nas maiores concentrações (1,5%) de tomilho e óleo de alecrim.(AU)

Analysis of the freezing point of milk by precision method and by Fourier Transform Infrared (FTIR) spectroscopy / [Análise do ponto de congelamento do leite pelo método de precisão e por espectroscopia no infravermelho por transformada de Fourier (FTIR)]

A total of 480 milk samples were analyzed in four repetitions with four preservative treatments (no preservative, Bronopol, Bronolat and Brononata), three storage times at temperatures up to 4 °C (24, 48 and 72hours after reception), five different water additions (0.0, 2.5, 5.0, 7.5 and 10.0%) and two analytical instruments (electronic cryoscope and FTIR). The objective of this study was to evaluate the effect of these parameters in the determination of the freezing point by the reference method and by Fourier transform infrared spectroscopy, thus determining the best analytical conditions and establishing a mathematical equation for electronic determination by FTIR spectroscopy. Bronolat was the best preservative and Brononata was the worst and is not recommended to analyze freezing point by FTIR. The storage time of the samples did not interfere in the analytical determinations by the precision method and by FTIR.(AU)

Foram analisadas 480 amostras de leite em quatro repetições em relação a quatro tratamentos por conservantes (sem conservante, bronopol, bronolat e brononata), três tempos de armazenamento, em temperatura até 4ºC desde a recepção da amostra (24, 48 e 72 horas), cinco porcentagens de adição de água (0,0; 2,5; 5,0; 7,5 e 10,0%) e dois instrumentos analíticos (crioscópio eletrônico e FTIR). O objetivo foi avaliar o efeito desses parâmetros na determinação do índice crioscópico pelo método de precisão em crioscópio eletrônico e por espectroscopia com transformada de Fourier no infravermelho, determinando-se, assim, as melhores condições analíticas. Entre os conservantes utilizados, bronolat foi o melhor e brononata foi o menos eficiente, não sendo, portanto, recomendado para análise de crioscopia por FTIR. O tempo de armazenamento das amostras não interferiu nas determinações analíticas pelo método de precisão e por FTIR.(AU)

The anticholesterol oxidation effects of garlic (Allium sativum L.) and leek (Allium ampeloprasum L.) in frozen fish burgers submitted to grilling.

This study determined the total phenolic content and antioxidant capacity of garlic (Allium sativum L.) and leek (Allium ampeloprasum L.), as well as evaluated their anticholesterol oxidation potential in fish burgers. The total phenolic contents were 1.1 ± 0.1 mg GAE/g FW to garlic and 1.3 ± 0.4 mg GAE/g FW for leek. Leek extract showed antioxidant activity index (1.3 ± 0.01) in DPPH and ß-carotene/linoleic acid assay (66.5 ± 1.6%); however, in ORAC assay, no statistic differences were observed (P > 0.05). Besides that, bioactive compounds of garlic and leek extracts were identified by ultra-high performance liquid chromatography-electrospray by ionization-mass spectrometry (UHPLC-ESI-MS). Fish burgers were prepared using different concentrations of leek and garlic and stored at -18 °C for 90 days. Thus, at days 0, 30, 60, and 90, the samples were grilled and analyzed as to their cholesterol and cholesterol oxidation products contents. Storage and grilling led to an increase in cholesterol oxidation products; however, addition of garlic and leek minimized cholesterol oxidation products formation. After 90 days, samples containing 3% leek + 0.5% garlic ware the most effective in inhibiting the cholesterol oxides formation during storage and showed the lowest increase in cholesterol oxidation products content (21.16%). Thus, the findings of this research indicate the potential application of garlic and leek as natural inhibitors of cholesterol oxidation in food. PRACTICAL APPLICATION: Garlic and leek have a set of bioactive compounds with a wide antioxidant capacity when used in meat foods such as fish burgers. Garlic and leek used as natural antioxidants perform well in the shelf life of fish burgers and can be substitutes for synthetic antioxidants in this type of product. The presence of both vegetables reduced the formation of prejudicial products to human health generated during the shelf life of the food.

Effect of natural extracts obtained from food industry by-products on nutritional quality and shelf life of chicken nuggets enriched with organic Zn and Se provided in broiler diet.

This study investigated the influence of an organic mineral-supplemented broiler diet on the quality of nuggets. The resulting chicken nuggets were enriched with inorganic and organic forms of Zn and Se. The nuggets were processed by incorporating extracts from food industry by-products (rosemary [RH and RL], hydroxytyrosol [HYT], pomegranate [P], grape [GS], and Harpagophytum [H]). The physiochemical, microbiological, and sensory characteristics of the chicken nuggets were evaluated over a 12-month period of frozen storage. The addition of natural extracts did not affect the pH, proximate composition, or color (CIELab) of the nuggets among samples. However, significative differences were found between month of analysis (range from pH 6.16 to 6.63; luminosity from 62.51 to 84.74; redness from 0.16 to 7.14; and yellowness from 10.80 to 33.77). In addition, the combination of phenolic compounds with Zn and Se retarded microbial growth and reduced protein and lipid oxidation, thus maintaining the sensory quality and extending the shelf life of this product. For instance, the combination of RL + GS reduced in 75% the microbiological growth regarding the control sample (C), while samples that incorporated RH + P or HYT + P + H presented 50% less than C. In addition, upon only incorporating organic minerals Zn and Se, microbiological deterioration is reduced in 15%. This mix was significantly effective at reducing the oxidative reactions of lipids and proteins by 40% and 50%, as measured after 9 and 12 mo of frozen storage, respectively. The addition of the natural extracts and Zn and Se did not adversely affect the acceptability of the meat product.

Impact of Natural and Artificial Sweeteners Compounds in the Sensory Profile and Preference Drivers Applied to Traditional, Lactose-Free, and Vegan Frozen Desserts of Chocolate Flavor.

The study developed traditional and light chocolate-flavor frozen dessert formulations, aimed at the general public, lactose intolerants, and vegans, and evaluated influences on quantitative sensory profiles and consumer acceptance with the replacement of sucrose by sweeteners in low-calorie versions. Twelve samples with different matrices were studied, sweetened with sucrose, sucralose, and stevia. The ideal concentration of sucrose (9%: dairy samples and 15%: vegan samples) was determined by the JAR scale. The sweetness equivalence was determined by the magnitude estimation method. The physical-chemical parameters were evaluated: pH, overrun, melting, and texture. The sensory profile evaluated through Quantitative Descriptive Analysis (QDA). The QDA data were correlated with acceptance data by partial least squares regression (PLS). The results showed that the substitution of traditional milk by lactose-free milk in the formulation did not change the characteristics of the chocolate ice cream. The use of sweeteners presented differences for milk flavor, bitter taste, bitter residual, and melting. The use of stevia extract was characterized by the presence of bitter taste, residual sweet and bitter that inhibited the perception of milk flavor, but not directly impacting the acceptance by consumers. The sucralose presented a profile closer to the sucrose, presenting lower intensity for the undesirable attributes such as bitter taste and residual bitter. There was no significant difference in the use of soy or rice protein in vegan versions, however, the use of sweeteners and body agents negatively impacted consumers' acceptance by attenuating the flavor of vegetable protein and raising gummy coating during the melting. PRACTICAL APPLICATION: This study shows the development and sensory profile of frozen chocolate desserts. Traditional and modified samples have also been produced for consumers with dietary restrictions such as vegans, vegetarians, lactose intolerants, and diabetics. Throughout the sensory and statistical analysis, it was identified how to replace sucrose by the natural glycoside sweetener of steviol, as well as the impact on the sensory profile and the acceptance of the different formulations. The results found may provide important information for researchers in food industries who need to produce frozen chocolate desserts for vegans, vegetarians, lactose intolerant, and diabetic consumers. Stevia and sucralose were good substitutes for sucrose in the formulation of frozen desserts without lactose, but not in vegan versions (with rice and soy protein).

Effects of Multiple Freeze-Thaw Cycles on Biochemical and Physical Quality Changes of White Shrimp (Penaeus vannamei) Treated with Lysine and Sodium Bicarbonate.

Freezing and thawing occur during storage, transportation, and retail display, leading to deterioration of frozen shrimp. The objective of this research was to investigate the change in quality of frozen white shrimp treated by lysine and NaHCO3 after multiple freeze-thaw cycles. Shrimp were soaked in lysine and lysine/NaHCO3 each at 1% (w/v) frozen in an air-blast freezer at -30 °C, and kept in a chest freezer (-18 ± 2 °C) for a week before they were thawed using tap water before the analysis (freeze-thaw cycle 1). The samples were subjected to five freeze-thaw cycles, which were repeated every week. Qualities of the samples were determined for thawing loss, cutting force, and total volatile basic nitrogen (TVB-N), as well as oxidation stability by using Rancimat. The use of lysine/NaHCO3 could significantly reduce thawing loss at all freeze-thaw cycles compared to the control and lysine treatment (P < 0.05). Similar results were found with TVB-N and the oxidation stability of the samples. A difference in cutting forces of the shrimp between lysine and lysine/NaHCO3 treatment was found when the frequency of freeze-thawing was increased to three cycles; it was lower than that in the control at all cycles. Histological study showed that the treatment with lysine/NaHCO3 led to the swelling of muscle fibers and fewer fragments at five freeze-thaw cycles. The results showed that lysine/NaHCO3 could effectively retard the quality loss from repeated freeze-thawing during frozen storage. PRACTICAL APPLICATION: Repeated freezing and thawing usually occur during storage, transportation, retail display or in restaurants, and in consumers' kitchens. The temperature at the manufacturing site and during transportation in a tropical country like Thailand is relatively high, and frozen food producers come across quality deterioration resulting from multiple freeze-thaw cycles occurring during transportation and storage. Frozen shrimp producers require research to improve product quality by adding nonphosphate food additives or, if possible, by using natural food ingredients instead of polyphosphate or sodium bicarbonate.

Aspectos tecnológicos e sanitários de pescados congelados industrializados / Technological and sanitary aspects of frozen industrialized fish

Pescados congelados industrializados (PCIs), são tratados por processos adequados de congelamento, em temperatura inferior a -25ºC. Nesse trabalho avaliou-se parâmetros tecnológicos, sanitários e nutricionais, e informações obrigatórias de rotulagem, quanto às formas de conservação e origem. Foram coletadas 57 amostras de PCIs em redes de supermercados na cidade do Rio de Janeiro, de maio à agosto de 2018. A verificação dos critérios estabelecidos para a rotulagem, em normas sanitárias permitiu avaliar o nível de conformidade das informações dos rótulos e das condições de exposição desses alimentos. Conclui-se que a segurança do consumidor do estado do Rio de Janeiro está comprometida, já que 70,2% das amostras encontraram-se fora do padrão em relação à temperatura de conservação e 7,08% não especificaram sua origem.

Efeitos do congelamento lento e rápido prévios à maturação na maciez da carne bovina / Effects of slow and fast freezing prior to aging on beef tenderness

Na presente pesquisa foi analisada a influência do congelamento lento (-20 °C, ar estático) e rápido (-25 °C, ar forçado) seguido da maturação (0 e 14 dias) na maciez de contrafilé de bovinos da raça Nelore. Apenas as amostras não-congeladas e maturadas por 14 dias apresentaram maiores (P < 0,05) valores de pH do que as demais. Não foi verificado efeito significativo para a PPC (média de 23,34%), enquanto que as purgas foram maiores nas amostras congeladas do que nas não-congeladas (2,52 x 11,06%), independentemente da taxa de congelamento. Amostras congeladas rapidamente apresentaram menores força de cisalhamento do que as congeladas lentamente, mas ambas não diferiram das amostras não-congeladas. Concluiu-se que o congelamento, mesmo em diferentes taxas, associado à maturação não influenciou a maciez da carne bovina.

Efeitos do congelamento prévio à maturação na aceitação sensorial da cor da carne bovina / Effects of freezing/thawing and aging on sensorial beef color

Objetivou-se avaliar o efeito do congelamento prévio a maturação (0 e 14 dias) sobre a aceitação sensorial da cor da carne bovina, comparando com amostras não-congeladas. O congelamento reduziu os valores de pH das amostras (de 5,58 para 5,48) e aumentou a proporção de oximioglobina (de 69 para 73%) nas amostras não-maturadas. Todos os índices de cor foram afetados pelo tempo de maturação, ficando mais claras (maior L*), com tonalidade vermelha mais alaranjada (maior h) e mais intensa (maior C*). O congelamento reduziu os valores de L*, sendo que as amostras congeladas e maturadas por 14 dias foram percebidas como mais claras e reduziu a intenção de compra dos avaliadores. Conclui-se que o congelamento tem pouco efeito sob a coloração da carne, mas a maturação subsequente reduziu a sua aceitação.

Absorção excessiva de água em carcaças de frangos comercializadas em Campo Grande, Mato Grosso do Sul, Brasil / Excessive absorption of water in poultry carcasses sould in Campo Grande, Mato Grosso do Sul State, Brazil

A carne de frango é a mais consumida no Brasil. O alto consumo acarretou no aumento da produção avícola e uma maior preocupação com os casos de fraudes por absorção excessiva de água em carcaças. Objetivou-se avaliar o percentual de água resultante do descongelamento em carcaças de frangos comercializadas em Campo Grande – MS. Foram avaliadas 30 amostras de frangos congelados, de cinco diferentes marcas, para avaliar o percentual de água resultante do descongelamento através do Método de Gotejamento ou Drip Test. Verificou-se que das 30 amostras analisadas, 23 (76,6%) estavam fora dos padrões estabelecidos pela legislação, por apresentarem absorção excessiva de água, que resultaram em maior gotejamento. O excesso de água absorvida indica falhas no processamento tecnológico e possível prática de fraude pelas indústrias.

Free and hidden fumonisins in raw maize and maize-based products from China.

The occurrence of free and hidden fumonisins in raw maize and maize-based products from China was investigated. A total of 58 samples were analyzed using high-performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Among all the samples, 66% were contaminated with free fumonisins above limits of quantitation, and a higher percentage of 86% was found for total fumonisins (free + hidden). The highest contamination levels were observed in dried maize kernels which appeared mouldy, with mean levels of 15,737 and 30,785 µg/kg for free and total fumonisins, respectively. Frozen maize kernels, fresh maize kernels, and maize starch samples exhibited the lowest contamination levels, with no more than 200 µg/kg of total fumonisins. Except for one sample, the concentrations of total fumonisins were greater than those of free fumonisins with all the samples, the ratios of total-to-free fumonisins varied between 1.1 and 5.2, with an average ratio of 2.0.