Polymorphic transitions of mixed triglycerides, SOS, in the presence of sorbitan monostearate

Several lipoamino acids were synthesized, in which n-octadecanoic acid (stearic acid) was coupled with the α-amino group of an amino acid. The products were characterized and their identities confirmed by advanced analytical techniques like Fourier transform infrared, 1 H nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. Their surface properties, such as critical micelle concentration (CMC) and foaming properties, biodegradability, and antimicrobial activity were also evaluated. The N-stearoyl amino acids (NSA) had low CMC values, and some of them showed good foaming properties. They were screened for antimicrobial activity against the gram-positive bacteria Staphylococcus aureus, Micrococcus luteus, and Bacillus cerceus, the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the yeast Candida albicans. All the compounds inhibited at least one of these organisms. N-Stearoyl proline was the most effective, the order of antimicrobial activity being aromatic NSA > acidic NSA > basic NSA. However, the effective inhibition by all the compounds indicates the desirability of more thorough investigation and suggests that some of these compounds may have potential utility as biostatic additives in commercial products. All NSA are highly biodegradable and can readily be removed under conditions of normal secondary sewage treatment.Paper no. J9653 in JAOCS 78, 897-902 (September 2001).

Section: Resultsmentioning

confidence: 99%

“…Balanced reaction for the carbonaceous oxygen demand: CH 3 (CH 2 ) 16 Determination of ThOD for N-stearoyl aspartic acid: ThOD = (58/2 + 2) mol O 2 /mol N-stearoyl aspartic acid [5] = 31 mol of O 2 /mol N-stearoyl aspartic acid × 32 g/mol O 2 = 839.09 g O 2 /mol N-stearoyl aspartic acid…”

Section: Resultsmentioning

confidence: 99%

Preparation, characterization, and surface and biological properties of N‐stearoyl amino acids

Sivasamy

Krishnaveni

Rao

2001

“…Therefore, they are often used to improve shelf-life stability of finished products. Indeed, several studies have shown that even little amounts of those amphiphilic molecules, added to fatty phases, influence the polymorphic transitions of triglycerides (4)(5)(6)(7)(8)(9)(10).…”

mentioning

confidence: 99%

Polymorphism of stabilized and nonstabilized tristearin, pure and in the presence of food emulsifiers

Elisabettini

Desmedt

Durant

1996

The polymorphism of tristearin (SSS) was studied by means of differential scanning calorimetry and powder X-ray diffraction. The influence of 5% in weight of different food emulsifters--i.e., 1-monostearin, sorbitan tristearate, and sugar mono-stearate~was also studied. Because polymorphism is sensitive to thermal treatment, two thermal conditionings were applied. According to the dynamic process (melting, quenching, and heating at 5~ SSS showed three polymorphic forms: ct, 13', and 131. The presence of the emulsifiers hindered the 13' ~ 13 transformation, and a destructured 132 form was recorded. According to the stabilization process (stabilization at 57~ for various periods of time), SSS showed two 13' forms: 13~ and 13' 1" Three hours of stabilization were necessary to recover the whole triglyceride under the 13 form. The emulsifiers slowed down the polymorphic transition rates. Indeed, after six hours of stabilization, mixtures of 13' and 13 were observed. Sugar monostearate seemed to have the most powerful effect on the transition kinetics because large amounts of (x form were detected.

“…Emulsifiers such as lecithin adsorb to the crystal interface and slow the sintering process. Also, the incorporated emulsifier acts as an impurity and lowers the melting temperature (9). However, these findings are often based on bulk oil and are not always applicable to emulsions.…”

mentioning

confidence: 99%

Demulsification of oil‐in‐water emulsion under freezing conditions: Effect of crystal structure modifier

Harada

Yokomizo

2000

The demulsification of oil-in-water (O/W) emulsions under freezing conditions is connected to fat crystallization in the oil droplet. Therefore, demulsification can be prevented by the use of oil with a low melting point, and also by lowering the O/W ratio. However, an oil with a low melting point, such as sunflower, is rather expensive, and the O/W ratio has a significant effect on the texture of emulsions. We searched for an oil that is suitable for the production of a freeze-stable emulsion and found that soybean oil has unique characteristics. Normally, emulsions are more unstable at lower temperatures; soybean oil emulsion is unstable at −10°C and stable at −20°C. This unique characteristic results from the following two reasons. First, the solid fat content of soybean oil is almost the same at −10 and −20°C. Second, small crystals form a larger network over a period of time, and the higher temperature promotes faster restructuring. This structure formation was microscopically observed with the use of a thermostated stage. Structure formation was suppressed with the addition of a crystal structure modifier, polyglycerol fatty acid full ester, which also suppressed coalescence.