Vitamin stability

Soluble solids uptake due to osmotic dehydration, in addition to improving color, aroma, and vitamin stability during both air drying and frozen storage, could also play a very important role in the preparation of new types of ingredients at reduced water activity (Torreggiani et al., 1988). Due to the... 

Garrett, E. R. (1956), Prediction of stability in pharmaceutical preparations III. Comparison of vitamin stabilities in different multivitamin preparations. /. Am. Pharm. Assoc. Sci. Ed., 45,470-473. 

Coehlo, M.B. (1994) Vitamin stability in premixes and feeds a practical approach. BASF Technical Symposium, Indianapolis, Indiana, 25 May, pp. 99-126. 

Garrett ER, Prediction of stability in pharmaceutical preparations, vitamin stability in liquid multivitamin preparations. JAPhA 1956 45 171-178. 

Dahl GB, Jeppson RI, Tengborn HJ. Vitamin stability in a TPN mixture stored in an EVA plastic bag. J Clin Hosp Pharm 1986 11 271-279. 

Smith JL, Canham JE, Wells PA. Effect of phototherapy light, sodium bisulfite, and pH on vitamin stability in total parenteral nutrition admixtures. J Parent Enter Nutr 1988 12 394-402. 

A disinfectant, moisturizer and vitamin stabilizer, this reduces corneocyte cohesion, enhancing penetration of the other active ingredients in the post-peel mask. 

Table 2 External factors influencing vitamin stability (Adapted from Hoffinann (2005)) ...

Native ovoflavoprotein (49 kDa, pf=5.1) has, as does ovomucoid, certain antinutritional effects, as it inhibits serine proteases (trypsin, chymotrypsin and also microbial proteases) and has antiviral activity. Ovomacroglobulin (ovostatin) is an inhibitor of serine, cysteine, thiol and metalloproteases and shows antimicrobial activity. Some antinutritional effects are also seen in the basic glycoprotein avidin in raw egg white (relative molecular weight of the monomer is 15.6 kDa). It contains four identical subunits (pf = 9.5), each of which binds one molecule of biotin to give an unavailable complex. However, the denatured avidin, for example in hard-boiled eggs, does not interact with biotin. The interaction of riboflavin with flavoprotein (32 kDa, pf = 4.0) has, on the contrary, a positive influence on vitamin stability. Cystatin acts as cysteine protease inhibitor, and shows antimicrobial, antitumor and immunomodulating activities. 

Physicochemical methods are the most commonly employed and include the phases of extraction, purification, and final analysis. All these steps are critical in the vitamin evaluation. Extraction steps can include several treatments, such as heat, acid or alkali conditions, enzymes, and solvents, and these treatments have several purposes, such as vitamin stabilization and their release from other food components. Cleanup steps remove interfering compounds and are not necessary in many methods. Final determination and quantification can be mainly carried out by chromatographic [Table 8.1 summarizes some common high-performance liquid chromatography (HPLC) methods applied to water-soluble vitamin analysis], spectrometric, enzymatic, inmunological, or radiometric techniques. 

Pullman and Pullman (1963), in their seminal book on quantum biochemistry, noted the central role occupied in life processes by molecules possessing partly or completely conjugated systems. These molecules include the coenzymes, whose precursors are the water-soluble vitamins. Stabilization of transition states by electronic delocalization, transmission of electronic perturbations over several atoms, and facilitation of electron mobility were suggested as explaining, at least in part, the reaction capabilities of coenzymes. An additional role for coenzymes (Jencks, 1975) is the provision for optimal binding interactions with specific subsites on the enzyme, the so-called "anchor principle" discussed above. In this section, we shall consider the mechanism of action of the major coenzymes. A general description of coenzyme reaction mechanisms is available (Lowe and Ingraham, 1974). 

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