Effects of Agar Gel Strength and Fat on Oral Breakdown, Volatile Release, and Sensory Perception Using in Vivo and in Vitro Systems

Abstract

The density and composition of a food matrix affect the rates of oral breakdown and in-mouth flavor release as well as the overall sensory experience. Agar gels of increasing concentration (1.0, 1.7, 2.9, and 5% agarose) with and without added fat (0, 2, 5, and 10%) were spiked with seven aroma volatiles. Differences in oral processing and sensory perception were systematically measured by a trained panel using a discrete interval time intensity method. Volatile release was measured in vivo and in vitro by proton transfer reaction mass spectrometry. Greater oral processing was required as agar gel strength increased, and the intensity of flavor-related sensory attributes decreased. Volatile release was inversely related to gel strength, showing that physicochemical phenomena were the main mechanisms underlying the perceived sensory changes. Fat addition reduced the amount of oral processing and had differential effects on release, depending on the fat solubility or lipophilicity of the volatiles.

Consumer Acceptability of Intramuscular Fat

“…Fat also plays a critical role in defining the sensory properties of complex foods, such as marbled beef. Apart from making food softer, fat facilitates “oral processing”, lubrication of food particles, increases saliva viscosity and acts as a binder or glue assisting in formation of a solid bolus in preparation for swallowing (Almiron-Roig, 2010; de Lavergne et al , 2015; Foster et al , 2011; Frank et al , 2015; Salles et al , 2011). There is increasing evidence for the existence of a long chain fatty acid taste receptor mechanism (Galindo et al , 2012; Tucker et al , 2014; Voigt et al , 2014) and human preferences for fat have been linked to variations in saliva flow and composition (Méjean et al , 2015; Mennella et al , 2014; Running et al , 2013).…”

“…As the level of marbling increases in meat, the bulk density decreases; there is less muscle fiber and collagen per unit volume of meat, potentially requiring less oral processing (Foster et al , 2011; Frank, 2015; Salles et al , 2011). Increasing levels of IMF may also contribute to meat tenderization by disrupting the organization of intramuscular connective tissue (Li et al , 2006).…”

“…This may increase the perceived intensity of the flavor (Chabanet et al , 2013; Lawrence et al , 2012). Similarly volatiles with low fat solubility (lipophobic molecules) may be released faster in the presence of significant levels of fat (Frank, 2015). Finally, fat has been shown to affect the rate of volatile release during eating in meat (Carrapiso, 2007; Lorido et al , 2015).…”

Dynamic Aroma Release from Complex Food Emulsions

“…The aroma of a processed food is one of the key quality parameters for its success in the market place, and aroma release over simple oil-in-water (o/w) emulsions (for example, milk, cream, mayonnaise, salad dressing) 1 has been studied widely. [2][3][4][5][6][7][8][9] Complex water-in-oil-inwater (w/o/w) emulsions are emulsions where the oil phase of o/w emulsions is partly replaced by an inner aqueous phase. Due to the complex structure, w/o/w systems can be used for bioactive encapsulation.…”

“…Factors such as emulsion composition and aroma hydrophobicity (the octanol-water partition coefficient, log P or log K ow ) influence dynamic aroma release over o/w emulsions. 3,4,[6][7][8][9] With regard to the impact of emulsion droplet size, dispersed volume fraction and emulsifier concentration on dynamic aroma release, published literature paints a controversial picture. On one hand side these factors are reported to have no impact, 4,6 on the other hand side impact of droplet size, affecting emulsion viscosity, on dynamic aroma release has been reported.…”