Organoleptic polysaccharides

The function of Jisper Uis fermentation appears to be primarily the breakdown of protein and polysaccharides by secreted proteases and amylases. Replacement oiPispergillis by chemical or enzymatic hydrolysis has no major impact on the organoleptic properties of the sauce. Likewise, inoculation with a pure culture of Ixictobacillus delbrueckii to carry out the acetic acid fermentation produces a normal product. The S. rouxii and Toru/opsis yeasts, however, are specifically required for proper flavor development. 

As described above, astringency is a very complex sensation that occurs in several foodstuff and beverages, involving different kinds of compounds (phenolic compounds, proteins), and that is affected by medium conditions (pH, alcohol, presence of other molecules in solution, etc.). This sensation constitutes one of the main organoleptic properties of red wine and has been a matter of research over the years for wine chemists. Winemakers believe that polysaccharides contribute to the mouthfeel volume of a wine, but this is a rather empirical observation. 

Morris, E. R. (1987). Organoleptic properties of food polysaccharides in thickened systems. In Industrial Polysaccharides, Yalpani, M. (Ed.), pp. 225-238. North-Holland, Amsterdam. 

Analysis shows that concentrations of polysaccharides and volatile fermentation products in white wines are reduced by tangential microfiltration, as compared to filtration through a kieselguhr precoat. Anthocyanins and tannins are affected in red wines. However, in view of the natural modifications that occur in wines during aging, these differences tend to become less marked over time. The standard tests used in organoleptic analysis did not identify any significant differences (threshold of 5%) after samples had been kept for 1, 6, and 12 months. 

Filtration throngh a coarse diatomaceous earth precoat (2.3 and 1.5 Darcy) did not affect chemical composition. The same operation with fine earth (0.35 Darcy) reduced the polysaccharide and condensed tannin content by 10%. No organoleptic effects were identified when the samples were tasted one month after filtration. 

Besides nutrients, foods contain many substances that influence the food sensory impression and its organoleptic properties. These food constituents are known as sensoriaUy active compounds. They determine the sensory value (quality) of foods, inducing an olfactory sensation (perception), which is described as the aroma, odour and smell, gustative perception, which is the taste, visual perception, which is the colour, haptic (tactile) perception, which is the touch and feel, and auditorial perception, which is the sound. The olfactory sensation is derived from odour-active compounds and the gustative perception from taste-active compounds. Flavour is the sensory impression determined by the chemical senses of both taste and smell and is caused by flavour-active food components. Haptic sensation is the texture, which is affected mainly by high molecular weight compounds, such as proteins and polysaccharides, often referred to collectively as hydrocoUoids. Geometric aspects of texture that evoke both haptic and visual sensations symbolise the terms appearance and shape. 

Polysaccharides in foods contribute to the formation of texture and also affect other organoleptic properties. Soluble polysaccharides are used in many food industry sectors and other fields as fillers, thickeners, to increase the viscosity of products, act as stabilisers of dispersions and some are thickening agents and gelling substances. 

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