Adding lysine and yeast extract improves sensory properties of low sodium salted meat.

The partial reduction of Sodium Chloride (NaCl) and the use of lysine, yeast extract and substitute salts Potassium Chloride (KCl) and Calcium Chloride (CaCl2) in the characteristics of salted meat was investigated. Proximate composition, physicochemical properties (pH, water activity, lipid oxidation), instrumental analysis (color, shear force), microbiological analysis (total counts, lactic acid bacteria counts, thermally tolerant coliforms, and total coliforms) and sensory evaluation (120 consumers) were performed. The partial replacement of NaCl by KCl and CaCl2 significantly reduced the sodium content of salted meat treatments, while lysine and yeast extract minimized the negative sensory effects due to the addition of KCl and CaCl2. The addition of lysine and yeast extract increased the sensory acceptance and decreased rancid aroma, salty taste, and aftertaste of salted meat made with a blend of NaCl + KCl + CaCl2, with no differences in the physiochemical quality parameters. Moreover, the treatments made with the blend NaCl + KCl exhibited characteristics similar to traditional salted meat formulations.

Selective attention to affective value alters how the brain processes olfactory stimuli.

How does selective attention to affect influence sensory processing? In a functional magnetic resonance imaging investigation, when subjects were instructed to remember and rate the pleasantness of a jasmine odor, activations were greater in the medial orbito-frontal and pregenual cingulate cortex than when subjects were instructed to remember and rate the intensity of the odor. When the subjects were instructed to remember and rate the intensity, activations were greater in the inferior frontal gyrus. These top-down effects occurred not only during odor delivery but started in a preparation period after the instruction before odor delivery, and continued after termination of the odor in a short-term memory period. Thus, depending on the context in which odors are presented and whether affect is relevant, the brain prepares itself, responds to, and remembers an odor differently. These findings show that when attention is paid to affective value, the brain systems engaged to prepare for, represent, and remember a sensory stimulus are different from those engaged when attention is directed to the physical properties of a stimulus such as its intensity. This differential biasing of brain regions engaged in processing a sensory stimulus depending on whether the cognitive demand is for affect-related versus more sensory-related processing may be an important aspect of cognition and attention. This has many implications for understanding the effects not only of olfactory but also of other sensory stimuli.

How pleasant and unpleasant stimuli combine in different brain regions: odor mixtures.

Many affective stimuli are hedonically complex mixtures containing both pleasant and unpleasant components. To investigate whether the brain represents the overall affective value of such complex stimuli, or the affective value of the different components simultaneously, we used functional magnetic resonance imaging to measure brain activations to a pleasant odor (jasmine), an unpleasant odor (indole), and a mixture of the two that was pleasant. In brain regions that represented the pleasantness of the odors such as the medial orbitofrontal cortex (as shown by activations that correlated with the pleasantness ratings), the mixture produced activations of similar magnitude to the pleasant jasmine, but very different from the unpleasant indole. These regions thus emphasize the pleasant aspects of the mixture. In contrast, in regions representing the unpleasantness of odors such as the dorsal anterior cingulate and midorbitofrontal cortex the mixture produced activations that were relatively further from the pleasant component jasmine and closer to the indole. These regions thus emphasize the unpleasant aspects of the mixture. Thus mixtures that are found pleasant can have components that are separately pleasant and unpleasant, and the brain can separately and simultaneously represent the positive and negative hedonic value of a complex affective stimulus that contains both pleasant and unpleasant olfactory components. This type of representation may be important for affective decision making in the brain in that separate representations of different affective components of the same sensory stimulus may provide the inputs for making a decision about whether to choose the stimulus or not.