Stability to oxidation

Stability to oxidation (induction period method) Oxygenates content... 

More recently considered candidates are large molecular anions with delocalized anionic charge, which offer low lattice energies, relatively small ion-ion interaction, and hence sufficient solubility and relatively large conductivity. Delocalization of the charge is achieved by electron-with drawing substituents such as -F or - CF3. Furthermore, these anions show a good electrochemical stability to oxidation. In contrast to Lewis acid-based salts they are chemically more stable with various solvents and often also show excellent thermal stability. 

Stndies of the antoxidation of carotenoids in liposomal suspensions have also been performed since liposomes can mimic the environment of carotenoids in vivo. Kim et al. stndied the antoxidation of lycopene," P-carotene," and phytofluene" " in liposomal snspensions and identified oxidative cleavage compounds. Stabilities to oxidation at room temperature of various carotenoids incorporated in pig liver microsomes have also been studied." The model took into account membrane dynamics. After 3 hr of reactions, P-carotene and lycopene had completely degraded, whereas xanthophylls tested were shown to be more stable. 

Because of their lower hydrophilicity and higher stability to oxidation, O-protected hydroxylamines are more convenient substrates for alkylation than hydroxylamine itself. Commercially available 0-benzylhydroxylamine was successfully alkylated with alkyl halides and alkyl sulfonates ". ... 

Keogh, M.K., O Kennedy, B.T., Kelly, J., Auty, M.A., Kelly, P.M., Fureby, A., Haahr, A.-M. (2001). Stability to oxidation of spray-dried fish oil powder microencapsulated using milk ingredients. Journal of Food Science, 66, 217-224. 

This study supports the hypothesis that high DE maltodextrins and syrup solids permit the formation of encapsulated products with excellent stability to oxidation. Different enzyme-hydrolyzed starches yielded encapsulated orange oils which varied in stability amylomaize and potato maltodextrins exhibited the poorest stabilities while normal corn, waxy corn, cassava, rice, and wheat glucose syrup solids yielded the best and approximately equivalent shelf-lives. Based on oil retention during drying, amylomaize, wheat, rice, and cassava yielded satisfactory products. 

To determine the position of glycosidic bonds in glycosphingolipids, periodate oxidation and methylation are widely used. A characteristic feature of the periodate oxidation of glycosphingolipids is the stability, to oxidation under mild conditions,179 of the D-glucose residue that is located at the beginning of the carbohydrate chain and substituted at 0-4 this seems to be associated with steric hindrance caused by the close location of the lipid moiety. 

PE/PP blends have also been studied in terms of stability to oxidation. Livanova shown that oxidative degradation reaches a maximum when PP is in an isotropic structure and minimum for an oriented one [90]. 

Food lipids possess an inherent stability to oxidation, which is influenced by the presence of antioxidants and pro-oxidants. After a period of relative stability (induction period), lipid oxidation becomes autocatalytic and rancidity develops. Thus, the typical time-course of autoxidation, as measured by the concentration of hydroperoxides, consists of a lag phase (induction) followed by the rapid accumulation of hydroperoxides, which reaches a maximum and then decreases as hydroperoxide decomposition reactions become more important. The longer the induction period, the more stable the food to oxidation (Lundberg, 1962). 

Cottonseed oil has long sold at a slight premium over soybean oil because of greater stability to oxidation, and desirable flavor in fried snack foods such as potato chips. However, gossypol content, and lower protein quality put the meal at a price disadvantage. Feeding whole cottonseed to dairy cattle, whose rumen microorganisms can detoxify... 

Soybeans owe their dominance of the oilseed market to the value of their protein, which is much greater than that of other oilseeds. Of the oilseed meals produced in 2003, 129.58 million MT out of a total of 185.69 milllion MT was soybean meal (1). Of the money made on extracting soybeans, the meal accounted for between 51% and 76% of the total in the last 10 years. Soybean oil of typical composition performs well as a salad oil, but it is usually hydrogenated for use as a margarine stock or frying oil. Soybean oil s stability to oxidation also is limited by its content... 

The compounds with tertiary phosphines are interesting because they have been prepared for all the three metals. Their stability to oxidation has the trend Pt > Pd > Ni. The compounds with tertiary di-and polyphosphines, which are even more stable, show the same increase in stability with the atomic number. The compounds with the phosphites are the more stable they have been obtained for all three metals and are not oxidized by air. 

As potentially more readily-available alternatives to natural a,-PI, the supply of which is limited, recombinant apPI (r-aj-PI) and a mutant form incorporating the previously suggested change of Met-358 to Val-358 (r-apPIvai) have been produced and expressed in yeast [69, 70]. In part, the valine mutant was chosen in order to test whether it would confer stability to oxidation. As hypothesized, the r-apPI ai form was shown to be resistant to both chemical oxidation [69] and to inactivation by neutrophils [71]. This result indirectly supported the proposal that Met-358 acts as a switch by which neutrophils inactivate aj-PI. Although both of these recombinant peptides are active as inhibitors of HLE, they are much less thermally stable and show significantly shorter half-lives in vivo than the native inhibitor [70], These differences have been ascribed to the fact that neither of these variants incorporates the carbohydrate side-chains found in native apPI. 

We report here on the use of alkyl sulfones as novel unconventional cosurfactants in CTAB-stabilized microemulsions. Sulfones, being fully oxidized at sulfur, have good stability to oxidants such as hypohalite. 

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