Brazilian consumers' perception of tenderness of beef steaks classified by shear force and taste Percepção pelos consumidores brasileiros da maciez da carne classificada pela força de cisalhamento e sabor

The knowledge of consumer perception of meat tenderness and taste is essential to forecast a Brazilian quality value-based beef market. This study aimed to verify perception of tender (WBSF < 4.1 kg) from tough (> 4.8 kg) strip loin steak or uncharacteristic (calcium-treated/Ca-IM) and normal (non-calcium/NO-Ca) meat taste by consumers according to gender, age, education and income levels. Steaks were previously classified by shear force measurements as tender or tough. Each consumer was served a paired sample of one tender and of one tough steak, which were either Ca-IM or NO-Ca treated before tenderness classification. Three hundred and eight consumers answered a nine-point intensity (tenderness) and hedonic (taste) scales evaluation questionnaire. Among consumers, 82.2% indicated beef as first choice meat products, 75.3% had beef at least four times a week; 39.3% considered taste as the most important meat attribute and 30.2% considered tenderness; 75.8% were males; 73.6% were 21 to 55 years old; 56.7% had college education; 76.6% had monthly income higher than US $435,00. Tender steaks were scored highest (P < 0.01), independently of gender, age and income. However, elderly consumers gave higher scores to tender steaks in comparison to middle age consumers (P < 0.05). In the lower education level, scores given to tender and tough meat did not differ. The higher income level responders assigned lower tenderness scores within tender or tough meat (P = 0.10). Differences in taste were perceived by both genders, and by consumers in every income and education level. Males gave higher scores (dislike less) within Ca-IM steaks. Consumers in the lower education level scored taste higher (like most) within untreated samples. The elderly people could not differentiate taste between the Ca-IM and NO-Ca steaks. These are the first indications that Brazilian consumers perceive tender from tough or uncharacteristic taste of beef, but palatability is evaluated differentially depending on gender, age, education and income level.<br>O conhecimento da percepção de maciez e sabor da carne bovina pelo consumidor é essencial para vislumbrar um mercado brasileiro que pague por qualidade. Este estudo avaliou a percepção diferenciada de contra-filé macio (WBSF < 4.1 kg) ou duro (> 4.8 kg), ou ainda com sabor não característico (imersão em Ca/ Ca-IM) ou normal (sem cálcio/ NO-Ca) de acordo com sexo, faixa etária, e nível de escolaridade formal e renda dos consumidores. Os bifes foram pareados em amostras macia/dura e Ca-IM/NO-Ca, e servidos a 308 consumidores que responderam a um questionário apresentando escalas de intensidade (maciez) e hedônica (sabor) de nove pontos. O perfil dos consumidores mostrava que: 82,2$ 1.000,00. De maneira geral, os bifes macios obtiveram notas mais altas (P < 0,01), independente de sexo, faixa etária e nível de renda. Entretanto, os idosos deram notas mais altas que os consumidores de meia idade em avaliações dos bifes macios (P < 0,05). No nível baixo de escolaridade não houve diferença nas notas para bifes macios e duros. Quanto mais alto o nível de renda, menor foram as notas dadas nas avaliações dos bifes macios ou duros (P = 0,10). Diferenças no sabor foram notadas por ambos os sexos, e por todos os níveis de escolaridade e renda. O sexo masculino conferiu notas mais altas (desgostou menos) quando consumia bifes Ca-IM. Consumidores do menor nível de escolaridade atribuiram notas maiores para sabor (gostaram mais) em bifes com sabor normal. Os idosos não diferenciaram sabor entre os bifes Ca-IM e NO-Ca. Estas observações são as primeiras indicações objetivas de que os consumidores brasileiros são capazes de perceber diferenças entre bifes macios e duros ou com sabor amargo e normal. Todavia, a palatabilidade é avaliada de forma diferenciada dependendo do sexo, faixa etária, e níveis de escolaridade e renda

Global variability in leaf respiration in relation to climate, plant functional types and leaf traits

Summary: Leaf dark respiration (R dark ) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of R dark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in R dark . Area-based R dark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8-28°C). By contrast, R dark at a standard T (25°C, R dark 25 ) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher R dark 25 at a given photosynthetic capacity (V cmax 25 ) or leaf nitrogen concentration ([N]) than species at warmer sites. R dark 25 values at any given V cmax 25 or [N] were higher in herbs than in woody plants. The results highlight variation in R dark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of R dark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs). © 2015 New Phytologist Trust

Global variability in leaf respiration in relation to climate, plant functional types and leaf traits

Leaf dark respiration (R-dark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of R-dark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in R-dark. Area-based R-dark at the prevailing average daily growth temperature (T) of each siteincreased only twofold from the Arctic to the tropics, despite a 20 degrees C increase in growing T (8-28 degrees C). By contrast, R-dark at a standard T (25 degrees C, R-dark(25)) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher R-dark(25) at a given photosynthetic capacity (V-cmax(25)) or leaf nitrogen concentration ([N]) than species at warmer sites. R-dark(25) values at any given V-cmax(25) or [N] were higher in herbs than in woody plants. The results highlight variation in R-dark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of R-dark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs)