Detection and quantification of groundnut oil adulteration with machine learning using a comparative approach with NIRS and UV-VIS.

Groundnut oil is known as a good source of essential fatty acids which are significant in the physiological development of the human body. It has a distinctive fragrant making it ideal for cooking which contribute to its demand on the market. However, some groundnut oil producers have been suspected to produce groundnut oil by blending it with cheaper oils especially palm olein at different concentrations or by adding groundnut flavor to palm olein. Over the years, there have been several methods to detect adulteration in oils which are time-consuming and expensive. Near infrared (NIR) and ultraviolet-visible (UV-Vis) spectroscopies are cheap and rapid methods for oil adulteration. This present study aimed to apply NIR and UV-Vis in combination with chemometrics to develop models for prediction and quantification of groundnut oil adulteration. Using principal component analysis (PCA) scores, pure and prepared adulterated samples showed overlapping showing similarities between them. Linear discriminant analysis (LDA) models developed from NIR and UV-Vis gave an average cross-validation accuracy of 92.61% and 62.14% respectively for pure groundnut oil and adulterated samples with palm olein at 0, 1, 3, 5, 10, 20, 30, 40 and 50% v/v. With partial least squares regression free fatty acid, color parameters, peroxide and iodine values could be predicted with R2CV's up to 0.8799 and RMSECV's lower than 3 ml/100 ml for NIR spectra and R2CV's up to 0.81 and RMSECV's lower than 4 ml/100 ml for UV-Vis spectra. NIR spectra produced better models as compared to UV-Vis spectra.

Comparative study on the antioxidant efficacy of Adinandra nitida extracts in inhibiting lipid oxidation in edible oils.

Exploring natural antioxidants is essential to delay lipid oxidation. This study investigated the inhibitory effect of Adinandra nitida (AN) extract in six edible oils, compared to TP and TBHQ. Methods included extract preparation, bioactive compounds analysis, in vitro antioxidant activities by FRAP, DPPH, and ABTS assays, fatty acid composition detection, and POV determination. The results showed that AN was rich in total flavonoids, total phenols and had better iron ion reduction ability than TBHQ. In oleic and linoleic acid-rich oils, AN significantly delayed early-stage lipid oxidation, outperforming TP and TBHQ. In linolenic acid-rich oils, AN maintained a stable effect. Molecular docking studies revealed strong binding interactions between main compounds and fatty acids, with Camelliaside A in (7.83) showing higher binding energy to linolenic acid than TBHQ (7.64), supporting the antioxidant effects. These findings suggest AN as a promising natural alternative to synthetic antioxidants, enhancing oil stability and shelf life.

Determination of fatty acid, cholesterol, alpha-tocopherol, and aroma components of traditionally and commercially produced Trabzon butters.

This study investigated 29 butter samples from Trabzon, Turkey. Cholesterol contents ranged from 134.13 to 325 mg/100 g, α-tocopherol contents ranged from 1.62 to 3.37 mg/100 g, and ß-carotene contents ranged from 4.46 to 15.60 µg/g. Fatty acid composition analysis showed variations, with palmitic acid ranging from 26.11 % to 44.25 %, oleic acid from 19.55 % to 29.80 %, and linoleic acid from 1.63 % to 3.04 %. A total of 44 aroma components were identified. Traditional butter samples exhibited differences in aroma components and fatty acid composition compared to commercial butter. Notably, traditional butter had higher concentrations of octanoic and n-decanoic acids than commercial butter. Moreover, some aroma components such as N-butanoic acid 2-ethylhexyl ester, decanoic acid, and pentadecane were found exclusively in traditional butters. Traditional butter showed higher α-tocopherol and ß-carotene contents. These findings underscore the distinct chemical profiles of traditional and commercial butter samples, influenced by production methods and possibly geographical origin.

Effects of pressure-based technologies on food lipids oxidation.

The aim of this paper is to provide a thorough review of recent research on the effects of high pressure processing (HPP) and hyperbaric storage (HS) on lipid oxidation amounts in different food products, as well as the mechanisms of lipid oxidation during processing and storage. Globaly, highly perishable foods showed an increase in lipid oxidation when preserved by HPP. On the other hand, HS using lower pressure levels but much longer time under pressure seems to cause a higher level of secondary lipid oxidation products and a lower level of tertiary products, with HS so decreasing oxidation progress during storage. Existing studies have mainly focused on individual oxidation indicators, highlighting the need for a comprehensive analysis of primary, secondary, and tertiary oxidation products in order to fully understand the progression of oxidation. This comprehensive approach ensures a systematic assessment of lipid oxidation, leading to a clear understanding of the oxidation process.

Effect of Linoleic and Linolenic Acid Contents on the Oxidation Stability of Interesterified Fats under Rancimat Test Conditions.

This study aimed to better understand the association between the amount of polyunsaturated fatty acids, namely, linoleic acid (LA) and linolenic acid (LNA), and the increases in the peroxide value that results from storing interesterified fats, which are used as sources of solid fats in edible oil and fat products, at high temperatures. Six interesterified fats with different LA and LNA contents were prepared and oxidized at 50°C, 60°C, 70°C, and 80°C under Rancimat test conditions. The oxidation rate increased with LA and LNA contents and increasing temperature. The oxidation kinetic analysis during the early oxidation stages demonstrated that when LA and LNA exceeded 8% and 2% respectively, the oxidative stability decreased as expected. However, the total LA and LNA contents had a higher correlation with the reaction rate constant [k (meq kg-1 h-1 )] than each amount of LA and LNA contained therein. In other words, the oxidation stability of the interesterified fats used in this study depended on the total LA and LNA contents.

Fortified edible oils in Bangladesh: A study on vitamin A fortification and physicochemical properties.

Food fortification has always been an effective and proven practice for eradicating various nutrient deficiencies in Bangladesh. This study investigated different quality parameters of three types (soybean, sunflower, and palm) of extensively consumed fortified edible oils in Bangladesh. Vitamin A analysis has shown that the vitamin A fortification level of most of the oil brands (73 %) did not comply with the Bangladesh Standard and Testing Institution (BSTI) standards (1.5-3.0 mg/100 g). Vitamin A contents of soybean, sunflower, and palm oil brands ranged from 0.13 to 2.06, 0.92-1.34, and 0.99-1.31 mg/100 g, respectively. Inter-brand values of vitamin A were also significantly different (p < 0.05). The majority of the samples were found to be within the acceptable ranges of Codex and BSTI, taking into account the significant chemical quality parameters for soybean, sunflower, and palm oil, such as acid value (0.31-0.93, 0.31-0.56, 0.39-0.81 mg KOH/g), free fatty acid (0.15-0.46, 0.15-0.28, 0.2-0.41 %), saponification (188.64-196.35, 186.53-188, 197.05-199.86 mg KOH/g), and peroxide values (0.06-2.9, 0.65-1.58, 1.35-1.75 meq O2/kg) respectively. All the brands' physical quality parameters (density, specific gravity, pH, viscosity, smoke point, color, and RI) complied with Codex standards. Various physical and chemical quality parameters were analyzed for significant correlations at 0.01 and 0.05 levels of significance. Remarkably, significant correlations were found between vitamin A and peroxide value (p < 0.01), iodine value and viscosity (p < 0.01), saponification value and viscosity (p < 0.01), pH and viscosity (p < 0.01), and saponification value and pH (p < 0.05). In conclusion, although the vitamin A status of most of the fortified edible oil brands was poor, the key quality indicators (except iodine value) of most of the oils were within the Codex and BSTI standard limits and were acceptable for human consumption.

A novel method for determination of peroxide value and acid value of extra-virgin olive oil based on fluorescence internal filtering effect correction.

Peroxide value (PV) and acid value (AV) are widely used indicators for evaluating oxidation degree of olive oils. Fluorescence spectroscopy has been extensively studied on the detection of oil oxidation, however, the detection accuracy is limited due to internal filtering effect (IFE). Due to the primary and secondary IFE, at least two wavelengths of absorption information are required. Least squares support vector regression (LSSVR) models for PV and AV were established based on two absorption coefficients (µa) at 375 nm and emission wavelength and one fluorescence intensity at corresponding wavelength. The regression results proved that the model based on 375 and 475 nm could reach the best performance, with the highest correlation coefficient for prediction (rp) of 0.889 and 0.960 for PV and AV respectively. Finally, the explicit formulations for PV and AV were determined by nonlinear least squares fitting, and the rp could reach above 0.94 for two indicators.

The bioprotective role of irradiated hibiscus against harmful effects of using repeatedly frying edible oil

Abstract Repeatedly frying process of dietary edible oil has a potential role in the generation of free radicals. Therefore, questions have always been raised as to whether, there is an efficient and economical method to reduce the harmful effects of repeated use of frying edible oil. Since hibiscus has been stated to have a wide variety of therapeutic effects, it was important to investigate its properties against harmful effects of free radicals. The current study aspires to find out whether irradiated powder of hibiscus has a protective role against adverse effects of repeated use of frying edible oil. Thirty-five adult male albino rats were equally assigned into five groups. First groupG1 was fed with normal diet as control group, meanwhile, groupG2 the diet mixed with fresh oil, G3 diet mixed with repeatedly frying oil only, G4 diet mixed with frying oil treated with hibiscus and G5 diet mixed with frying oil treated with irradiated hibiscus. Feeding duration was six weeks. Fatty acid analyses of oil as well as peroxide values were determined. Blood and liver samples were collected for biochemical analyses as well as histological study. Repeatedly heated cooked oil has significant increases in peroxide value, acid value, free fatty acid and both conjugated diene and triene compared with repeatedly frying oil treated with hibiscus. Also there are significant increases in cholesterol and triglyceride and impaired in liver functions in G3compared with others. In addition, relative to the hibiscus groups, there is a substantial reduction in oxygen consumption in G3. Both hibiscus as well as irradiated hibiscus attract attention in order to play a vital and economical role against harmful effects of frequent use of frying edible oil on some biological functions but, irradiated hibiscus was more effective.

Resumo O processo de fritura repetida de óleo comestível da dieta tem papel potencial na geração de radicais livres que podem ter efeitos prejudiciais em algumas funções biológicas. Portanto, sempre se questionou se existe uma maneira eficiente e econômica de prevenir ou pelo menos reduzir os efeitos nocivos do uso repetido de óleo comestível para fritar. Como o hibisco tem ampla variedade de efeitos terapêuticos, foi importante investigar suas propriedades como agente antioxidante contra os efeitos nocivos dos radicais livres. O presente estudo pretende descobrir se o pó irradiado de hibisco tem papel protetor contra os efeitos adversos do uso repetido de óleo comestível para fritar. Trinta e cinco ratos albinos machos adultos foram divididos igualmente em cinco grupos. O primeiro grupo G1 foi alimentado com dieta normal como grupo controle, enquanto o grupo G2 dieta misturada com óleo fresco, dieta G3 misturada com óleo de fritura repetida, dieta G4 misturada com óleo de fritura tratada com hibisco e dieta G5 misturada com óleo de fritura tratada com hibisco irradiado. A duração da alimentação foi de seis semanas. Foram determinadas as análises de ácidos graxos de óleo, bem como os valores de peróxidos. Amostras de sangue e fígado foram coletadas para análises bioquímicas e estudo histológico. O óleo cozido repetidamente aquecido tem aumentos significativos no valor de peróxido, valor de ácido, ácido graxo livre e dieno e trieno conjugados em comparação com óleo de fritura repetidamente tratado com hibisco. Também há aumentos significativos no colesterol e triglicérides e comprometimento das funções hepáticas no G3 em comparação com outros. Além disso, em relação aos grupos de hibiscos, há uma redução substancial no consumo de oxigênio no G3. Tanto o hibisco como o hibisco irradiado chamam atenção por desempenhar papel vital e econômico contra os efeitos nocivos do uso frequente de óleo comestível para fritar em algumas funções biológicas, mas o hibisco irradiado foi mais eficaz.

The bioprotective role of irradiated hibiscus against harmful effects of using repeatedly frying edible oil / O papel bioprotetor do hibisco irradiado contra os efeitos nocivos do uso de óleo comestível para fritar

Abstract Repeatedly frying process of dietary edible oil has a potential role in the generation of free radicals. Therefore, questions have always been raised as to whether, there is an efficient and economical method to reduce the harmful effects of repeated use of frying edible oil. Since hibiscus has been stated to have a wide variety of therapeutic effects, it was important to investigate its properties against harmful effects of free radicals. The current study aspires to find out whether irradiated powder of hibiscus has a protective role against adverse effects of repeated use of frying edible oil. Thirty-five adult male albino rats were equally assigned into five groups. First group"G1" was fed with normal diet as control group, meanwhile, group"G2" the diet mixed with fresh oil, "G3" diet mixed with repeatedly frying oil only, "G4" diet mixed with frying oil treated with hibiscus and "G5" diet mixed with frying oil treated with irradiated hibiscus. Feeding duration was six weeks. Fatty acid analyses of oil as well as peroxide values were determined. Blood and liver samples were collected for biochemical analyses as well as histological study. Repeatedly heated cooked oil has significant increases in peroxide value, acid value, free fatty acid and both conjugated diene and triene compared with repeatedly frying oil treated with hibiscus. Also there are significant increases in cholesterol and triglyceride and impaired in liver functions in "G3"compared with others. In addition, relative to the hibiscus groups, there is a substantial reduction in oxygen consumption in "G3". Both hibiscus as well as irradiated hibiscus attract attention in order to play a vital and economical role against harmful effects of frequent use of frying edible oil on some biological functions but, irradiated hibiscus was more effective.

Resumo O processo de fritura repetida de óleo comestível da dieta tem papel potencial na geração de radicais livres que podem ter efeitos prejudiciais em algumas funções biológicas. Portanto, sempre se questionou se existe uma maneira eficiente e econômica de prevenir ou pelo menos reduzir os efeitos nocivos do uso repetido de óleo comestível para fritar. Como o hibisco tem ampla variedade de efeitos terapêuticos, foi importante investigar suas propriedades como agente antioxidante contra os efeitos nocivos dos radicais livres. O presente estudo pretende descobrir se o pó irradiado de hibisco tem papel protetor contra os efeitos adversos do uso repetido de óleo comestível para fritar. Trinta e cinco ratos albinos machos adultos foram divididos igualmente em cinco grupos. O primeiro grupo "G1" foi alimentado com dieta normal como grupo controle, enquanto o grupo "G2" dieta misturada com óleo fresco, dieta "G3" misturada com óleo de fritura repetida, dieta "G4" misturada com óleo de fritura tratada com hibisco e dieta "G5" misturada com óleo de fritura tratada com hibisco irradiado. A duração da alimentação foi de seis semanas. Foram determinadas as análises de ácidos graxos de óleo, bem como os valores de peróxidos. Amostras de sangue e fígado foram coletadas para análises bioquímicas e estudo histológico. O óleo cozido repetidamente aquecido tem aumentos significativos no valor de peróxido, valor de ácido, ácido graxo livre e dieno e trieno conjugados em comparação com óleo de fritura repetidamente tratado com hibisco. Também há aumentos significativos no colesterol e triglicérides e comprometimento das funções hepáticas no "G3" em comparação com outros. Além disso, em relação aos grupos de hibiscos, há uma redução substancial no consumo de oxigênio no "G3". Tanto o hibisco como o hibisco irradiado chamam atenção por desempenhar papel vital e econômico contra os efeitos nocivos do uso frequente de óleo comestível para fritar em algumas funções biológicas, mas o hibisco irradiado foi mais eficaz.

How heated vegetable oil age? Effect of the container of heating on ageing.

This study compares the ageing process of heated oil with unheated oil and assesses the effect of container used in heating on ageing. Four types of oils were heated on glass, copper and iron. The samples were allowed to age for 1 year. Unheated oils generally produce peroxide faster (for unheated maximum increase in 6-month is 2907 % from 1.351 to 40.627 but for heated maximum increase is 6574 % from 1.91 to 127.476). But they develop secondary oxidation products slowly (for unheated maximum increase in 6-month is 884 % from 1.553 to 15.29 but for heated maximum increase is 191 % from 6.42 to 18.72). For most oil heating in copper produce more p-anisidine value during ageing. The acid value of only unheated oils decreases between 6 months to 1 year. For the 1st six-month rate of increase in saponification value in unheated oil is much higher. The DPPH inhibition activity also changes differently.

Influence of Ageing Time and Method on Beef Quality and Safety.

The effectiveness of dry ageing with regard to retaining meat quality is still subject to debate. At 4 d post mortem, samples of boneless strip loins were excised from young Charolais carcasses and then stored for a further 26 d in a cooler, either vacuum-packaged (VP) or dried-aged (DA). Loin samples were also dissected 7 d post mortem as a control treatment (CT). Chemical, instrumental and microbiological data (n = 18) were determined in longissimus dorsi and underwent ANOVA to estimate the differences in the ageing fixed factor split into two orthogonal contrasts: control vs. aged and VP vs. DA. Ageing loss (both surface dehydration and water purge) was greater in DA compared to VP samples, resulting in the lowest moisture content and highest crude protein and fat percentage in DA loins. The ageing method did not affect meat surface colour, except for redness, which had the lowest value in DA samples. Meat tenderness improved a similar amount following both VP and DA ageing treatments. Compared to the control, prolonged ageing raised both the peroxide value and the total microbial count, especially in DA samples, though both remained within the recommended limits. In summation, both ageing methods improved beef meat tenderisation, preserving its shelf life.

Thermal stability of levopimaric acid and its oxidation products.

Biofuels are renewable alternatives to fossil fuels. Levopimaric acid‒base biofuels have attracted increasing attention. However, their stability remains a critical issue in practice. Thus, there is a strong impetus to evaluate the thermal stability of levopimaric acid. Through thermogravimetry (TG) and a custom-designed mini closed pressure vessel test (MCPVT) operating under isothermal and stepped temperature conditions, we investigated thermal oxidation characteristics of levopimaric acid under oxygen atmosphere. Thin-layer chromatography (TLC) and iodimetry were used to measure the hydrogen peroxides generated by levopimaric acid oxidation. A high pressure differential scanning calorimeter (HPDSC) was used to assess hydroperoxide thermal decomposition characteristics. Gas chromatography-mass spectrometry (GC-MS) was used to characterize the oxidation products. The thermal decomposition kinetics of levopimaric acid were thus elucidated, and a high peroxide value was detected in the levopimaric acid. The decomposition heat (QDSC) and exothermic onset temperature (Tonset) of hydroperoxides were 338.75 J g-1 and 375.37 K, respectively. Finally, levopimaric acid underwent a second-stage oxidation process at its melt point (423.15 K), resulting in complex oxidation products. Thermal oxidation of levopimaric acid could yield potential thermal hazards, indicating that antioxidants must be added during levopimaric acid application to protect against such hazardous effects.

Shelf-life improvement of raw milk using ethanolic extracts of selected medicinal plants (Moringa stenopetale, Artemesia anua and MenthaSpicata).

The current study was designed to examine the Shelf life extension ability and antioxidant activity of the ethanolic extracts processed from Moringa stenopetale, Artemesia anua and Mentha Spicata. The raw milk and preservative plants was collected from Chencha woreda, Arba Minch. Purposive sampling techniques were used for collection of milk and plant samples. The crude extracts were isolated from three plant species using Soxhlet extraction method and characterized for the presence of bio-active compounds qualitatively and quantitatively. He accelerated shelf-life testing method was used to estimate the shelf-life of milk samples. Deterioration was tracked using measurements of the peroxide values and sensory characteristics. The DPPH free radical scavenging assay was used to determine the antioxidant capacity of various extracts, and the absorbance was measured at 517 nm. Mentha Spicata had the highest TPC value of 2.842 ± 0.109 mg GAE/g, while Moringa stenopetale had the lowest at 0.285± 0.0098 mg GAE/g. Similarly, Moringa stenopetale had the greatest TTC value of 69.86 ± 1.25 mg QE/g, while Mentha Spicata had the lowest at 46.2 ± 0.7 mg QE/g. The extracts of Moringa stenopetale, Artemesia anua, and Mentha Spicata showed good antioxidant activities, with IC50 values of 39.490 ± 0.029, 61.189± 0.058, and 68.062± 0.014 g/mL, respectively. The shelf-life of the milk sample improved with Moringa stenopetale was 6.99 days at 27 °C. Generally, Moringa stenopetale had the longest shelf life of all the plant extracts tested for milk samples.

Physicochemical characteristics and shelf-life stability of soya bean oil-based shortening.

The use of animal fats as raw material for shortening production has been avoided because of low supply, and religious restrictions of certain beliefs. The use of hydrogenated vegetable oils is also avoided because that may induce cardiovascular diseases. Palm oils and soya bean oil are theoretically potentials to be used as raw materials for shortening manufacturing due to their triacylglycerols composition and these oils can be easily modified to achieve desirable plasticity. In this study, shortening was produced by formulating a blend of palm stearin and soya bean oil in varying proportions. Physicochemical properties, product stability, and sensory acceptability of the processed shortening were determined. Stability tests of the processed shortening were determined for 6 months at two months intervals. The acidity, peroxide value, and free fatty acid values were increased with storage time and storage temperature. The physicochemical properties of the processed shortening samples were within the requirements of the food domain. The samples stored at 37 °C exhibited the highest acid, peroxide, and free fatty acid values throughout storage time. In conclusion, shortening produced from 60% palm stearin (S60) and stored at room temperature has shown a good physicochemical characteristic and is well accepted for different sensory attributes.

Assessing the Impact of Roasting Temperatures on Biochemical and Sensory Quality of Macadamia Nuts (Macadamia integrifolia).

Depending on the temperature regime used during roasting, the biochemical and sensory characteristics of macadamia nuts can change. 'A4' and 'Beaumont' were used as model cultivars to examine how roasting temperatures affected the chemical and sensory quality of macadamia nuts. Using a hot air oven dryer, macadamia kernels were roasted at 50, 75, 100, 125, and 150 °C for 15 min. The quantity of phenols, flavonoids, and antioxidants in kernels roasted at 50, 75, and 100 °C was significant (p < 0.001); however, these kernels also had high levels of moisture content, oxidation-sensitive unsaturated fatty acids (UFAs), and peroxide value (PV), and poor sensory quality. Low moisture content, flavonoids, phenols, antioxidants, fatty acid (FA) compositions, high PV, and poor sensory quality-i.e., excessive browning, an exceptionally crunchy texture, and a bitter flavor-were all characteristics of kernels roasted at 150 °C. With a perfect crispy texture, a rich brown color, and a strong nutty flavor, kernels roasted at 125 °C had lower PV; higher oxidation-resistant UFA compositions; considerable concentrations of flavonoids, phenols, and antioxidants; and good sensory quality. Therefore, 'A4' and 'Beaumont' kernels could be roasted at 125 °C for use in the industry to improve kernel quality and palatability.

The Effects of Heat Treatment on the Oxidation Resistance and Fatty Acid Composition of the Vegetable Oil Blend.

The purpose is to elucidate the effects of the duration of heat treatment on the resistance of vegetable oils to oxidative processes. Iodine and acid values were analyzed before and after heat exposure. Rapeseed oil, sunflower oil, and a blend of rapeseed and sunflower oils (ratio 55:45) were used as samples. Sunflower oil heated at a temperature of 40°C for 80 minutes had its peroxide value increased by 3.0 times (p ≤ 0.05) as compared to rapeseed oil and the blend. At 75°C, the peroxide value increased by 4.0 times for sunflower oil (p ≤ 0.05), by 3.0 and 3.3 times for rapeseed oil (p ≤ 0.05), and by 3.1 and 3.4 times for the blend (p ≤ 0.05). At 40°C, no peroxide values were obtained that exceeded the threshold limits. The concentration of fatty acids in oils depends on the plant variety, growth conditions and maturity of seeds or fruits. Therefore, the concentration of fatty acids in the oil should be measured before oil blending.

Characterization of Composite Film of Gelatin and Squid Pen Chitosan Obtained by High Hydrostatic Pressure.

In the present study, gelatin-based films incorporating squid pen chitosan obtained by high hydrostatic pressure (HHP chitosan) at varying proportions were prepared and their properties were compared with films containing untreated chitosan. The resulting films were characterized by analyzing the physical, morphological, mechanical and barrier properties. The addition of different ratios of HHP chitosan to the gelatin-based film yielded significant improvements in mechanical and moisture barrier properties. The reason for this might be that HHP chitosan contributed to a regular and dense microstructure of the composite films due to forming a three-dimensional network structure in gelatin-based films with enhanced intermolecular interactions. The FTIR spectra showed no new chemical bond formed by incorporating HHP chitosan into gelatin-based film. The SEM micrographs showed that the gelatin-based film fabricated with three types of chitosan had a homogeneous surface morphology, indicating good compatibility of the materials. Compared to the gelatin-based films containing untreated chitosan, films containing HHP chitosan significantly delayed oxidative deterioration in oil during storage. Therefore, the chitosan obtained by HHP treatment could have a potential application in edible gelatin-based films as packaging materials.

Correlation of tangible quality parameters of vegetable-based transformer fluids.

Due to the inherent environmental footprint of petroleum derived transformer fluids, the power industry is gradually exploring the potential of vegetable oils as alternatives. The impetus comes mostly from vegetable oils renewability and their inherent biodegradability. However, the major drawback in the use of vegetable oils as dielectric fluids is their lower oxidative stability and higher kinematic viscosity compared to mineral oils. The results obtained clearly demonstrate the correlation between spectroscopic data induction time, kinematic viscosity, acid value, and peroxide value. Quantitatively, the absorption frequencies of functional groups in vegetable oil transformer fluids that can be correlated to the mentioned quality parameters show noticeable changes with aging/oxidative degradation. The study also demonstrates the utility of integrating spectroscopic data to understand trends in induction time and kinematic viscosity of oil samples heated under transformer service conditions.

Frozen Ready-to-(h)eat Meals: Evolution of Their Quality during a Real-Time Short Shelf Life.

The purpose of this experimentation was to study the evolution of the quality of two types of blast-frozen ready-to-(h)eat meals, tortellini and a vegetable soup, during a short shelf life of 70 days. The analyses, performed in order to identify any variations resulting either from the freezing process or from the subsequent storage, carried out at the temperatures of -30 °C and -18 °C, respectively, examined the consistency of the tortellini and the soup, the acidity and the peroxide value of the oil extracted from them, the phenols and carotenoids present in the soup, the volatile compounds in the tortellini and the soup, and a sensory analysis of both products. The results showed that, during the 70 days of shelf life, there was no variation in the texture of the tortellini, but there were changes in the consistency of the soup, which decreased as the days of storage went on. Furthermore, statistically significant increases (p < 0.05) in the acidity and in the peroxide value of the oil of the soup were observed during the storage period; however, no statistically significant difference (p > 0.05) in the peroxide value of the oil of the tortellini was found. Moreover, no quantitative changes were observed in the phenolic compounds and carotenoids in the soup or in the volatile substances of either product. Finally, the sensory analysis confirmed, together with the chemical data, that the blast-freezing process adopted was suitable to maintain the good quality of these fresh meals, even if some technical modifications (in particular, lower freezing temperatures) should be adopted to improve the final quality of the products.

Effect of Different Genotypes and Harvest Times of Sage (Salvia spp. Labiatae) on Lipid Oxidation of Cooked Meat.

Lipid oxidation is the primary non-microbial reason for quality deterioration of meat and meat products. Lipid oxidation can be prevented or delayed by antioxidants. In this study, 15 sage (Salvia spp. Labiatae) extracts (five genotypes, three harvest times) were tested for their ability to reduce lipid oxidation (peroxide value (PV) and thiobarbituric acid reactive substances (TBARS)) in ground, uncured, cooked porcine and bovine meat (60%/40% mixture) during 14 days of refrigerated storage. Additionally, total phenolic content was determined, and the antioxidant capacity of the extracts was measured as radical scavenging activity (2,2-diphenyl-1-picrylhydrazyl assay), reducing power, and superoxide anion scavenging activity. All 15 sage extracts were able to reduce lipid oxidation, though showing expected differences depending on genotype and harvest time. The extracts of S. officinalis accession from Foggia, Italy performed better than the other genotypes when looking at the entire storage period and considering both PV and TBARS. Of the applied methods for determining antioxidant capacity, superoxide anion scavenging activity proved to be the best determinant of the ability of sage to reduce lipid oxidation in the meat sample.