A Simple and rapid method was developed for measuring the degree of rancidity in food fat. The new method is based on using heptane to extract the oil in foods, instead of benzene in previously proposed “benzene distillation method”. The recoveries of carbonyl compounds especially C6 aldehyde with “heptane distillation method” were satisfactory for this purpose. The developments of rancidity in fried rice crackers were measured by sensory evaluation and chemical tests such as the measurement of peroxide value (POV) and volatile carbonyl value (VCV) with heptane distillation method. The results showed a good correlation between the VCV and flavor score when POV and VCV were increasing. In the stage when POV or VCV were decreasing, no correlation or a reverse correlation was found between flavor score and VCV. This was infered to be caused by the oxidation of aldehydes to acids. Comparing Figs. -4 and 5, mixing of spices such as curry powder to foods was apt to mislead the judgment on the flavor score of autoxidized oils in fried rice crackers.
Effect of solvent relative humidity on removal of water-soluble soils from wool fabric has been studied in the solution of 0.1M Aerosol OT in hexane at 20°C. Five kinds of inorganic salts, potassium bromide, ammonium chloride, sodium chloride, sodium bromide, and potassium thiocyanate, were used as model water-soluble soils. A saturated aqueous solution of each salt has different relative humidity. The relative water vapor pressure over the solution was measured by an electric hygrometer. In general the removal of each salt increased markedly in the vicinity of 75% solvent relative humidity independently of each intrinsic relative humidity of the saturated aqueous solutions of these salts. Though these experimental results did not conform to the Fulton's theory on removal of water-soluble soils in drycleaning, they were explained in relation to the state of water absorbed by wool in nonaqueous solutions reported in our previous papers.
It is known that palm oil has a peculiar flavor. However, little information has been obtained on this flavor. To know the flavor compounds characteristic for palm oil, palm oil was fractionated into several fractions by vacuum distillation and saponification, and the organoleptic test of each fraction was carried out. The results indicate that carbonyl-free fractions separated from volatile compounds have distinct palm oil-like flavor. In an other experiment, β-carotene was heated at 200°C for 20min and fractionated into eight fractions by TLC and it was recognized that some fractions showed palm oil-like taste. It seemed to be important for reducing palm oil flavor to remove thermal decomposition products of β-carotene as much as possible.
The foaming components were fractionated from keratin hydrolysate by membrane ultrafiltration. Molecluar weights, surface tensions, foam heights, and foam stabilities of the above fractions were determined. The molecular weight range of the main foaming components was estimated to be from 1.0×104 to 5.0×103 by means of membrane ultrafiltration. Fractions were subject to gel filtration using TSK-Gel G3000SW and G2000SW in order to check the molecular weight ranges of the membrane ultrafiltrates. The molecular weight of the most abundant component of each fraction was found to correspond well to the molecular weight of the component fractionated by the membrane except those of the molecular weight below 10, 000.
A liquid crystalline (LC) phase having the lamellar structure separated from a cetostearyl alcohol-surfactant-water ternary system was similar to the LC phase in situ in the stability to temperature behavior. Microscopical observation clarified that the LC phase appeared at the alcohol-water interface at 60°C and solidified at 55°C. The freezed LC is considered to contribute to the stabilization of the emulsified ternary system by forming networks in the aqueous phase
Theoretical double bond distribution in the positional isomerization of higher straight chain monoolefins (carbon number n+1) has been investigated by considering the formation of j (=1, 2, …, n) -isomer of which double bond being located between j-th and j+1-th carbon to be in conformity with a stochastic process. The molar fraction of j-isomer at reaction time t can be considered as a probability x (j/t) having parameter t (≥0). The probability mass function x (j/t) is basically expressed as follows; _??_ of which initial conditions to be given by _??_ where u (k/t) is a probability of being positionally isomerized k (=0, 1, …, ∞) times for the reaction time t and v (j/k) is a probability of the formation of j-isomer after being positionally isomerized k times. The u (k/t) is given by the probability of Poisson process of which parameter is λ. The v (j/k) depends upon the mechanism of positional isomerization, and it is given by the probability of binomial distribution in case of the mechanism via half-hydrogenated state as well as via π-allylic state. The probability mass function x (j/t) is finally deduced to _??_ _??_ The function shows that the stochastic process of the double bond distribution is one of the compound Poisson processes. The mean of j at reaction time t : <j>t is equal to that at reaction time 0 : <j>0; <j>t=νx (ν/0) +ξx (ξ/0) +…+ρx (ρ/0) =<j>0 and the variance of j at reaction time t : σjt2 is given by σjt2=1/2λt+σj02 σj02= (ν-<j>0) 2x (ν/0) + (ξ-<j>0) 2x (ξ/0) +…+ (ρ-<j>0) 2x (ρ/0), where σj02 is the variance of j at reaction time 0. Hence using the experimental data of σjt2 and σj02, the parameter λ which is considered to be a first order reaction rate constant of the double bond distribution is determined by the following equation; _??_ Theoretical results of the double bond distribution were in good agreement with experimental data presented by Shiina, Subbaram, and Knegtel.
The adsorption equilibrium of water soluble saturated linear alcohols on the surface modified and unmodified active carbons in aqueous solutions was examined. An active carbon, Pittsburg Active Carbon (Calgon Co.), was used as an adsorbent, and this was treated with various oxidants such as nitric acid, hydrochloric-hydrofluoric acid, air, oxygen, ozone. Saturated linear alcohols used in this experiment were from ethanol to 1-octanol. The adsorption isotherms were made in accordance with Freundlich equation, and Traube's law was applied in this experiment. The adsorption capacity of saturated linear alcohols on the active carbon was less than that of fatty acids of C2-C4, but saturated linear alcohols of C5-C8 showed a reverse result in dilute solutions. The adsorption capacity of 1-butanol on the active carbon modified by various oxidants decreases in the following order : HCl-HF>ozone>O2>unmodified>HNO3>air.