Slow cold-stabilization

Table 1.16. Influence of pre-treatment on the physicochemical parameters of a cold-stabilized white wine. Wines treated with slow cold-stabilization (10 days at —4°C). Assessment of protective effects (Maujean et al., 1985)...

Slow Cold Stabilization, Without Tartrate Crystal Seeding... 

In cold stabilization, cold temperatures are used to cause precipitation of excess potassium acid tartrate out of the wines. If allowed enough storage time at very cold winter temperatures, this precipitation will take place. Under California winter conditions, this reduction of excess tartrates is very slow,... 

Chemical Reactivity - Reactivity with Water Forms hydrogen chloride (hydrochloric acid). Reaction not very vigorous in cold water Reactivity with Common Materials Slow corrosion of metals Stability During Transport Stable Neutralizing Agents for Acids and Caustics Flush with and rinse with sodium bicarbonate or lime solution Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Chemical Reactivity - Reactivity with Water Hot water may cause frothing. Reaction with cold water is slow and non-hazardous Reactivity with Common Materials No reaction Stability During Transport Stable Neutralizing AgerUs for Acids and Caustics Solid spills can usually be recovered before any significant reaction with water occurs. Flush area of spill with water Polymerization Very unlikely at ordinary temperatures, even in the molten state Inhibitor of Polymerization None. 

It is frequently the case that organic peroxides, and the hydroperoxides in particular, cannot be analyzed by GLC in the usual way, as they undergo decomposition inside the instrument. A study on the thermal stability of various organic peroxides shows that on using the cold on-column injection technique, with the temperatures of the injection port and column as low as practically possible and applying slow heating rates, it is possible to... 

Almond Prunus dulcis, P. amygdalis, Amygdalis communis). Almond oil is generally considered as an oleic-rich oil (65-70%), but its fatty acid composition can vary widely. The triacylglycerol composition of the oil has also been reported. Low-saturated, high-monounsamrated oils show high oxidative and cold weather stability (i.e., they are slow to deposit crystals) (65, 66). 

Slow stabilization often causes loss of color (OD at 520 nm) in both red and white wines. It is therefore recommended that the length of treatment is reduced by adding small particles of cream of tartar, which are easier to maintain in a homogeneous suspension. Another advantage of seeding is that the wine may be maintained at a less cold temperature (—2°C instead of -4°C). 

An example of the first type is the use of low-acid, low-salt, and low-temperature spin-baths, which slow down the cellulose regeneration sufficiently to yield HWM polynosic rayon [190]. Another example is the Lilienfeld process for which the viscose, made from unaged alkali cellulose with excess carbon disulfide and only a short ripening, is spun into a cold spin-bath containing 50-85% of sulfuric acid. This is a case of stabilizing the xanthic acid. Rayon produced in this way has tenacities greater than 5 g/den. 

The effects due to very slow processes in the sample, however, may not be removed even in the quasi-isothermal MTDSC with data collection after 10 min. The analysis of the slow response of the sample in the glass transition region will be treated in Section 4.3. The decrease in the heat capacity due to cold crystallisation can easily be converted into a plot of the crystallisation kinetics. Additional points for the kinetics plot can be generated at shorter and longer analysis times of the quasi-isothermal runs. The time-scale can easily be adjusted to modulations from 1 min to many hours, limited only by the patience of the operator and the stability of the calorimeter. 

The work of the plant breeder, however, is extremely slow and there is always the possibility that breeding in desired characteristics or breeding out undesired characteristics is accompanied by the elimination of other desirable features such as cold-or disease-resistance or high yield. Attempts to breed out the high linolenic acid content of soybean oil to improve flavour and oxidative stability have been disappointing. 

Fermentation itself can be stopped when the desired alcohol content is reached, either by removal of yeast (filtration, centrifugation) or by their deactivation (pasteurization). A further possibility is to create fermentation conditions, which suppress yeast metabolism (Narziss, Miedaner, Kem, Leibhard, 1992). The most practical tool to suppress yeast metabolism is low temperature. This method is called the cold contact process (CCP) , which ensures very slow ethanol prodnction while other metabolic processes, snch as formation of higher alcohols and esters or reduction of carbonyls, may exhibit moderate activities (Perpete Collin, 1999). After interrupting the fermentation at an alcohol content less than 0.5% voL, the AFB is usually matured for at least 10 days at 0-1 °C to enrich flavour and improve the colloidal stability. Then the product is filtered, carbonated, stabilized and sterilized (Branyik, Silva, et al., 2012 Burberg Zamkow, 2009). 

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