Vibrational overtone initiated unimolecular dissociation of HOCH_2OOH and HOCD_2OOH: Evidence for mode selective behavior

The vibrational overtone induced unimolecular dissociation of HMHP (HOCH2OOH) and HMHP-d2 (HOCD2OOH) into OH and HOCH2O (HOCD2O) fragments is investigated in the region of the 4nuOH and 5nuOH bands. The unimolecular dissociation rates in the threshold region, corresponding to the 4nuOH band, exhibit measurable differences associated with excitation of the OH stretch of the alcohol versus the peroxide functional group, with the higher energy alcohol OH stretching state exhibiting a slower dissociation rate compared to the lower energy peroxide OH stretch in both HMHP and HMHP-d2. Predictions using the Rice–Ramsperger–Kassel–Marcus theory give rates that are in reasonably good agreement with the measured dissociation rate for the alcohol OH stretch but considerably differ from the measured rates for the peroxide OH stretch in both isotopomers. The present results are interpreted as suggesting that the extent of intramolecular vibrational energy redistribution (IVR) is different for the two OH stretching states associated with the two functional groups in HMHP, with IVR being substantially less complete for the peroxide OH stretch. Analysis of the OH fragment product state distributions in conjunction with phase-space theory simulation gives a D0 value of 38±0.7 kcal/mole for breaking the peroxide bond in HMHP

The effect of ultrasound pretreatment on some selected physicochemical properties of black cumin (Nigella Sativa)

Background In the present study, the effects of ultrasound pretreatment parameters including irradiation time and power on the quantity of the extracted phenolic compounds quantity as well as on some selected physicochemical properties of the extracted oils including oil extraction efficiency, acidity and peroxide values, color, and refractive index of the extracted oil of black cumin seeds with the use of cold press have been studied. Methods For each parameter, three different levels (30, 60, and 90 W) for the ultrasound power and (30, 45, and 60 min) and for the ultrasound irradiation time were studied. Each experiment was performed in three replications. Results The achieved results revealed that, with enhancements in the applied ultrasound power, the oil extraction efficiency, acidity value, total phenolic content, peroxide value, and color parameters increased significantly (P 0.05). Conclusions In summary, it could be mentioned that the application of ultrasound pretreatment in the oil extraction might improve the oil extraction efficiency, the extracted oil’s quality, and the extracted phenolic compounds content.info:eu-repo/semantics/publishedVersio

Lipid oxidation kinetics of ozone-processed shrimp during iced storage using peroxide value measurements

In this research, in situ generated ozone exposure/wash cycles of 1, 3, and 5 min applied to shrimp samples either before (BIS) or during iced storage (DIS) has been used to study the lipid oxidation kinetics using the peroxide values (PV). The induction period (IP) as well as PV at end of the IP (PVIP) have been obtained. The rate constants (k) as well as half-lives (t1/2) of hydroperoxides formation for different oxidation stages were calculated. The results showed that both IP and PVIP were lower with BIS (IP between 4.35±0.09 and 5.08±0.23 days; PVIP between 2.92±0.06 and 3.40±0.18 mEq kg−1) compared with DIS (IP between 5.92±0.12 and 6.14±0.09 days; PVIP between 4.49±0.17 and 4.56±0.10 mEq kg−1). The k value for DIS seemed to be the greater compared to BIS. In addition, whilst decreases and increases in t1/2 were found at propagation, respectively, for BIS and DIS, decreases and increases were only found at the induction of oxidation stage(s) for BIS. Further, the PV of ozone-processed samples would fit first order lipid oxidation kinetics independent of duration of ozone exposures. For the first time, PV measurements and fundamental kinetic principles have been used to describe how increasing ozone exposures positively affects the different oxidation stages responsible for the formation of hydroperoxides in ozone-processed shrimp

Pendugaan Masa Kadaluwarsa Dendeng Lumat Ikan Patin (Pangasius Hypophthalmus) pada Kemasan Aluminium Foil

The research was to estimate the shelf life of catfish dendeng stored at room temperature (270C) and refrigerated temperature (50C). About 15 kg catfish weighing 600-800 gr each was obtained from a fish market in Pekanbaru. Two groups of dendeng prepared from catfish meat and the products were packed in aluminium foil and stored respectively at room temperature and refrigerated temperature for 49 days. Changes in the quality were analysed for peroxide value and moisture; and the shelf life was estimated by peroxide value and moisture using Arrhenius method. The results indicated that the shelf life of dendeng stored at room temperature and refrigerated temperature had a shelf life of 19,68 days and 26,69 days respectively. Peroxide value the dendeng stored at room temperature and refrigerated temperature at rejection was 21,17 and 18,82 meq/ 1000 g sample respectively; and moisture was 10,904% and 10,867% respectively

Effect of storage periods and packaging materials on the proximate and chemical properties of frozen blue whiting (Micromesistius poutassou) at different exposure time

This research seeks to determine the effect of storage periods and packaging materials on the proximate and chemical properties of frozen blue whiting (Micromesistius poutassou) at different exposure time – 0 hour, 2 hours and 4 hours, on arrival at the laboratory. Frozen M. poutassou were bought and stored in a commercial cold room for 12 weeks at -10oC and packed in different packaging materials (Ziploc bag, foil paper and carton) with un-wrapped samples for analysis which lasted 90 days and was conducted every 14 days to measure the moisture, protein, fat, ash, fibre and nitrogen free extract (NFA) content of the fish sample as well as iodine value, peroxide value, saponification value, acid value, free fatty acid and hydroxyl value of fish oil. The result clearly reveals that during storage, the different packaging materials showed significantly (p<0.05) decreasing trend in protein, lipid, ash, fibre and NFA content with increasing storage period and time of analysis except for the moisture content that showed opposite trend. For the chemical properties, the saponification value, peroxide value, free fatty acid, acid value and hydroxyl value showed significantly (p<0.05) increasing trend in the different packaging materials with increasing storage period and time of analysis. While the iodine value decreased with increasing period of storage and time of analysis; the iodine, saponification, peroxide and hydroxyl values were not within the acceptable limits

Polymers of triglycerides generated during heating of fat do not protect linoleic acid from ruminal biohydrogenation

Heating fats often induces a decrease of cis-9, cis-12 C18:2 and cis-9, cis-12, cis-15 C18:3 biohydrogenation (BH) in vivo (Gonthier et al. 2005), in situ (Troegeler-Meynadier et al. 2006) and in vitro (Privé et al. 2010). This is of interest because it could increase polyunsaturated fatty acids (PUFA) content of ruminant products. Temperature and duration of heating of sunflower oil affect ruminal BH of PUFA, in part due to peroxide value (Privé et al., 2010). Our hypothesis was that polymers of triglycerides (TG), formed during heating of TG but not of free FA, could be responsible for partial protection of PUFA from BH

Thermal oscillations in the decomposition of organic peroxides: Identification of a hazard, utilization, and suppression

The purpose of this research is to identify and characterize oscillatory thermal instability in organic peroxides that are used in vast quantities in industry and misused by terrorists. The explosive thermal decompositions of lauroyl peroxide, methyl ethyl ketone peroxide, and triacetone triperoxide are investigated computationally, using a continuous stirred tank reactor model and literature values of the kinetic and thermal parameters. Mathematical stability analysis is used to identify and track the oscillatory instability, which may be violent. In the mild oscillatory regime it is shown that, in principle, the oscillatory thermal signal may be used in microcalorimetry to detect and identify explosives. Stabilization of peroxide thermal decomposition via Endex coupling is investigated. It is usually assumed that initiation of explosive thermal decomposition occurs via classical (Semenov) ignition at a turning point or saddle-node bifurcation, but this work shows that oscillatory ignition is also characteristic of thermoreactive liquids and that Semenov theory and purely steady state analyses are inadequate for identifying a thermal hazard in such systems

Effect of high peroxide value fats on performance of broilers in normal and immune challenged states

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 18, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Thesis advisor: Dr. Jeffre D. Firman.M.S. University of Missouri--Columbia 2009.A series of trials were conducted in order to determine the effects of high peroxide value fats on performance of broilers in normal and immune challenged states from 0-49 days of age. In the first experiment, birds were fed one of six diets formulated to meet NRC requirements. Three levels of fat rancidity were utilized, each with and without the addition of an antioxidant. The results from this trial indicate that diets with a peroxide value of 75 or greater resulted in poorer feed conversion than treatments with low peroxide values. Furthermore, the addition of an antioxidant to the diets with a peroxide value of 75 or greater yielded improved feed conversion over diets with the same peroxide value but no antioxidant. The second trial was conducted in order to determine the effects of rancid fat on immune function in broilers. Birds received the same six dietary treatments. At 4 weeks of age, the birds underwent a coccidial challenge. No significant effects of the immune challenge in combination with peroxide levels on bird performance were observed. Overall, the results from these trials indicate that the inclusion of high peroxide value fats can cause a depression in overall live performance parameters, especially feed conversion, but that the addition of an antioxidant can improve bird performance. In the second trial, birds seemed to overcome the administered immune challenge.Includes bibliographical references

Production of fish cake from carp and its shelf life in cold store at -18°C

The increase in production of warm water fishes in Iran, such as carp, produces a need for development of new methods of food production for human consumption. In this research four formula for production of fish cake from carp were investigated. Using the chosen formula which consisted of 52% deboned carp meat, 28% potato, 10% whole egg, 8% flour and 2% of a mixture of garlic, ginger, nutmeg, pepper powder and salt, the fish cake was made. Then during 120 days at 18°C, according to a time schedule, the samples were tested for changes in their total volatile base, peroxide value and total count of bacteria. The results indicate that changes in TVB were from 14.0 to 18.9 mg/100g, peroxide value changed from 4.0 to 4.9 mg/kg. The total count of bacteria for all of the samples was negative. The shelf life of carp cake as the result of peroxide value increase was estimated to be 90 days at 18°C in cold store. This carp cake contains 20% protein, 8% oil, 10% carbohydrate, 6% ash and 56% moisture

PENGARUH FREKUENSI PENGGORENGAN TERHADAP PENINGKATAN PEROKSIDA MINYAK GORENG CURAH DAN FORTIFIKASI VITAMIN A

Background: Palm oil industry in Indonesia is divided into two there are cooking oil and branded cooking oil. Currently there area variety of branded cooking oil advantages, one of which is the fortification of vitamin A. Based on previous research it is known that 90% of house holds do frying as much as 4-8 times per day. Cooking oil used repeatedly can oxidize (react with air) so increasing levels of peroxide. Consumption of cooking oil containing high peroxide can cause health problems such as gastrointestinal irritation, diarrhea, and cancer. This study aims to determine the effect of the increase in the frequency of frying peroxide on cooking oil and cooking oil fortification of vitamin A was used. Method: This was experimental research with quasy experimental design. The research object in this study was cooking oil and vitamin A fortification of cooking oil used to fry out. Peroxide measurements made on a grill to 0, 1, 2, 3, 4 with three repetitions in each cooking oil. Result: On average the lowest peroxide contained in the zero frying process was equal to 5.27 MekO2/Kg (cooking oil) and 0.83 MekO2/Kg (vitamin A fortification of cooking oil) and continued to increase until the fourth frying at 18.86 MekO2/Kg (cooking oil) and 17.48 MekO2/Kg (vitamin A fortification of cooking oil). Cooking oil used repeatedly peroxide can affect the increase in cooking oil (P value 0.010) and vitamin A fortification of cooking oil (P value 0.012) and no differences peroxide between cooking oil and vitamin A fortification oil (p value 0.065). Conclusion: There were the influence of the frying process to the increased frequency of peroxide value on cooking oil. There were the effect of the increase in the frequency of peroxide value frying cooking oil fortification on vitamin A. There was no difference between the peroxide cooking oil and vitamin A fortification of cooking oil. Keywords: cooking oil, difference, fortification, peroxide value, fryin