In order to find the influences of antioxidant addition and storage temperature on stability, induction period of safflower biodiesel stabilized with propyl gallate whose concentration spreads from 0 ...to 5,000 ppm was studied by Rancimat method at the temperature range of 100–120°C. Kinetics on its oxidation was described by the first order rate law. In order to improve the oxidation stability of biodiesel economically, Klason lignin was introduced to supercritical treatment during biodiesel production. It was consequently found that the rapeseed biodiesel prepared by supercritical methanol method at 300°C / 20 MPa for 20 min with a small amount of lignin addition had the induction period longer than 6 h at 110°C in Rancimat test.
Optimisation of extra virgin olive oil quality Monteleone, E; Caporale, G; Carlucci, A ...
Journal of the Science of Food and Agriculture/Journal of the science of food and agriculture,
19/May , Letnik:
77, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This study investigated the correlation between total polyphenol content and the stability (ie induction time by Rancimat) of oil samples according to different regions, cultivars, extraction ...technologies and ripening times of raw material. Results indicate a correlation of oil stability with total polyphenols, (r = 0.88), a chemical variable easy to determine. We have set up an oil quality index as a measure of desirability including legal parameters, especially the Council Olive Oil International score (COI Score), stability (phenol content) and process yield into account. The study of the effects of olive ripening and storage prior to processing and olive paste mixing times and temperatures on the quality index using an experimental factorial design (24) were investigated. The process variables selected in the experimental factorial design were studied and the main effects on desirability were identified. Based on this information, the extraction process was optimised for quality index in relation to fruit ripening and olive paste mixing time using a response contour to identify optimal experimental conditions. This innovative procedure shows that process conditions can be optimised as a function of D tot, evaluated according to scientific determinations.
A simple and relatively inexpensive procedure to obtain 90% eicosapentaenoic acid + docosahexaenoic acid concentrates from sardine oil involved a two‐step winterization of the oil (10 and 4°C), ...followed by saponification and selective precipitation of saturated and less unsaturated free fatty acids by an ethanolic solution of urea. Antioxidant effects of butylated hydroxytoluene, dl‐α‐tocopherol, and two natural antioxidants, quercetin and boldine, added to the concentrate (0.5% wt/vol), were compared in the Rancimat at 60°C. dl‐α‐Tocopherol was unable to inhibit concentrate oxidation. Butylated hydroxyanisole and butylated hydroxytoluene had induction periods of 1.7–1.8 h compared to the control (1.0 h). A mixture of quercetin + boldine (2:1 w/w) significantly increased the induction period to 4.5 h.
Oxidative decay of oil is causing changes in its chemical, sensory and nutritional properties and is considered a major problem effecting loses in quality and nutritional value. This paper ...investigated the influence of the Lamiaceae plant extracts addition on oxidative stability of fish oil. The test was performed under accelerated oxidation by Rancimat method where different concentrations of herb extracts (basil, thyme and oregano) as well as effect of different temperatures were studied. Fatty acid profile of oil was analysed using gas chromatography. As expected, the applied temperature had significant impact on fish oil stability and the induction periods were prolonged after the addition of herb extracts. The best results at 80°C were obtained after addition of basil extract what resulted with induction period of 4.60 h. The addition of higher concentrations also resulted with prolonged induction periods; for oregano extract the results were dose-dependent, after addition of 50 and 100 µL of thyme extract the induction period remained the same (0.32 h), while the highest concentration of basil extract, probably due to presence of some components that acts as a prooxidants, resulted with lower IP value.
Analysis of Spray Dried Encapsulates Ishwarya S., Padma; Anandharamakrishnan, C
Spray Drying Techniques for Food Ingredient Encapsulation,
2015, 2015-10-30
Book Chapter
Characterization of the encapsulated product is significant in understanding the properties that govern its end applications. The analysis of spray dried encapsulates can be classified as: those ...related to its physical properties; those which indicate the efficiency of the encapsulation process and the product stability; and those which demonstrate the functionality of the microcapsules for which purpose the core was encapsulated. In this context, this chapter is intended to provide a compilation of the well‐established and most commonly used methodologies for the analysis of spray dried encapsulates. The analytical techniques described in this chapter include those for the determination of particle size and shape, encapsulation efficiency, stability, core release and taste masking. Determination of encapsulation efficiency and microcapsule stability are discussed for different core categories, including flavors, specialty oils, vitamins, polyphenolic compounds and probiotic cells, with appropriate case studies.
Thermally processed tannic acid (PTA) showed stronger antioxidant capacity and antimicrobial activity by Rancimat
® and disc diffusion tests than fresh tannic acid (FTA).
Soybean oil treated with PTA ...had 33–84% longer induction period (IP) of oxidation (8.0–14.7
h) than FTA treated oil (6.0–8.0
h), while untreated oil (control) showed only 5.9
h IP. The IP was increased (
p
<
0.05) with increased processing time up to 15
min, with no changes thereafter. The PTA samples had strong antimicrobial activity (inhibition zone diameter ⩾12
mm) on 10 tested human pathogens while the FTA samples showed antimicrobial activity only on two strains,
Salmonella Typhimurium (ATCC 14028) and
Enterobacter sakazakii MSDH over 1- and 2-day incubation periods.
13C NMR spectra showed that PTA had a higher content of hydrolysed aromatic carboxylic acid groups than FTA. The results showed that thermally processed tannic acid for 15
min had about 67% higher antioxidant capacity and about 50% higher antimicrobial activity than its fresh counterpart. Thermal processing could be useful for enhancing antioxidant capacity and antimicrobial activity of hydrolysable polyphenols in natural plants.
