Blue light-induced lipid oxidation and the antioxidant property of hypotaurine: evaluation via measuring ultraweak photon emission.

The effects of blue light on human body have attracted attention. The human skin in contact with the outside environment is often exposed to blue light, and the effects of this exposure remain to be fully determined. Therefore, in this study, we investigated the effect of blue light, at the intensity typically found in sunlight, on lipids in the skin from an oxidation perspective. Peroxide value (POV) and ultraweak photon emission (UPE) measurements were conducted to evaluate lipid oxidation. Our results confirmed that blue light irradiation induced lipid oxidation, similar to ultraviolet A (UVA) irradiation. Also, the effects of various reagents on the blue light-induced UPE were evaluated; however, the results differed from those of the DPPH radical-scavenging ability. We speculated that this is due to the difference in the evaluation principle; nevertheless, among reagents, hypotaurine not only showed a high antioxidant effect but was also more effective against blue light-induced oxidation than UVA. Based on the difference in the antioxidant effect of the lipid sample in this study, the oxidation reaction induced by blue light may be different from the UVA-induced reaction. Our study provides new insights into the effects of blue light on lipids in the human skin, thereby promoting research regarding photooxidation.

Oxidative Stability of Cottonseed Butter Products under Accelerated Storage Conditions.

Cottonseed is a natural product of cotton (Gossypium spp.) crops. This work evaluated the oxidative stability of cottonseed butters through accelerated autoxidation by storage at 60 °C for 25 days. Three oxidative stability parameter values (peroxide value, p-anisidine value, and total oxidation value) were monitored over the storage time. These chemical measurements revealed that the storage stability of the butter products was dominated by primary oxidation of lipid (oil) components, while the secondary oxidation levels were relatively unchanged over the storage time. An analysis of the tocopherols (natural oxidants in cottonseed) suggested not only the protection function of the molecules against oxidation of the cottonseed butter during storage, but also the dynamic mechanism against the primary oxidation of lipid components. Attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR) data confirmed no changes in the major C functional groups of cottonseed butters over the storage time. On the other hand, characteristic minor peaks of conjugated dienes and trienes related to lipid oxidation were impacted by the accelerated storage. As each day of accelerated oxidation at 60 °C is equivalent to 16 days of storage at 20 °C, observations in this work should have reflected the oxidative stability behaviors of the cottonseed butters after about 13 months of shelf storage under ambient storage conditions. Thus, these data that were collected under the accelerated oxidation testing would be useful not only to create a better understanding of the autooxidation mechanism of lipid molecules in cottonseed butters, but also in developing or recommending appropriate storage conditions for cottonseed end products to prevent them from quality degradation.

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.

Evaluation of the Effect of Elite Jojoba Lines on the Chemical Properties of their Seed Oil.

Jojoba oil (JO) extracted from seeds has outstanding properties, including anti-inflammatory, antioxidant, and antibacterial activities, and can be stored forlong periodsof time. The unique properties of jojoba oil depend on its chemical composition; therefore, the effect of the jojoba genotype on the chemical properties and active components of the seed oil was evaluated in this study. Oil samples were collected from 15 elite Egyptian jojoba lines. The chemical composition, such as moisture, crude fiber, crude oil, ash, and crude protein of elite lines' seeds was determined to investigate the variation among them based on the jojoba genotype. In addition, the iodine value was obtained to measure the degree of jojoba oil unsaturation, whereas the peroxide number was determined as an indicator of the damage level in jojoba oil. Fatty acid composition was studied to compare elite jojoba lines. Fatty acid profiles varied significantly depending on the jojoba genotype. Gadoleic acid exhibited the highest percentage value (67.85-75.50%) in the extracted jojoba oil, followed by erucic acid (12.60-14.81%) and oleic acid (7.86-10.99%). The iodine value, peroxide number, and fatty acid composition of the tested elite jojoba lines were compared withthose reported by the International Jojoba Export Council (IJEC). The results showed that the chemical properties of jojoba oils varied significantly, depending on the jojoba genotype.

Contemporary Developments and Emerging Trends in the Application of Spectroscopy Techniques: A Particular Reference to Coconut (Cocos nucifera L.).

The number of food frauds in coconut-based products is increasing due to higher consumer demands for these products. Rising health consciousness, public awareness and increased concerns about food safety and quality have made authorities and various other certifying agencies focus more on the authentication of coconut products. As the conventional techniques for determining the quality attributes of coconut are destructive and time-consuming, non-destructive testing methods which are accurate, rapid, and easy to perform with no detrimental sampling methods are currently gaining importance. Spectroscopic methods such as nuclear magnetic resonance (NMR), infrared (IR)spectroscopy, mid-infrared (MIR)spectroscopy, near-infrared (NIR) spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy, fluorescence spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy (RS) are gaining in importance for determining the oxidative stability of coconut oil, the adulteration of oils, and the detection of harmful additives, pathogens, and toxins in coconut products and are also employed in deducing the interactions in food constituents, and microbial contaminations. The objective of this review is to provide a comprehensive analysis on the various spectroscopic techniques along with different chemometric approaches for the successful authentication and quality determination of coconut products. The manuscript was prepared by analyzing and compiling the articles that were collected from various databases such as PubMed, Google Scholar, Scopus and ScienceDirect. The spectroscopic techniques in combination with chemometrics were shown to be successful in the authentication of coconut products. RS and NMR spectroscopy techniques proved their utility and accuracy in assessing the changes in coconut oil's chemical and viscosity profile. FTIR spectroscopy was successfully utilized to analyze the oxidation levels and determine the authenticity of coconut oils. An FT-NIR-based analysis of various coconut samples confirmed the acceptable levels of accuracy in prediction. These non-destructive methods of spectroscopy offer a broad spectrum of applications in food processing industries to detect adulterants. Moreover, the combined chemometrics and spectroscopy detection method is a versatile and accurate measurement for adulterant identification.

Inhibition of browning via aqueous gel solution of Aloe vera: a new method for preserving fresh fruits as a case study on fresh kernels of Persian walnut.

Aloe Vera (AV) gel is commonly used as a natural, inexpensive, edible coating that can improve the quality and shelf life of fruits. The objective of this study was to evaluate how two methods of applying AV, i.e. as an edible coating (dry environment) and as a gel solution (aqueous environment: a new method), prevent browning and maintain quality characteristics of fresh kernels of Persian walnut for 60 days during cold storage. Distilled water was used as a control group for both environments. In general, AV caused a reduction in the peroxide value (POV) of kernels, while preserving Total Phenolic Compound and Total Antioxidant Activity (TAA). The AV treatment slowed down the process of color change and maintained sensory properties during storage, compared to the control groups of both methods. The AV gel solution performed better than the AV edible coating in terms of POV, color (L* and h°) and microbial growth. In contrast, the AV edible coating was more effective in preserving TPC and TAA. Also, TAA was found to have a significant, positive correlation with L* and, simultaneously, a negative correlation with POV. As far as we know, this is the first instance that the AV gel was used as a formulated solution and as an edible coating on fresh fruits. This innovative method can be used in commercial practice, while being ecofriendly and non-chemical as a treatment for the maintenance of postharvest quality in fruits.

Effects of active batter coatings enriched by quince seed gum and carvacrol microcapsules on oil uptake and quality loss of nugget during frying.

ABSTRACT: The effects of active batter coatings containing quince seed gum (QSG) and carvacrol microcapsules (CM) on oil uptake, moisture loss, lipid oxidation, texture, color and organoleptic properties of chicken nuggets during the frying process were investigated. Active coatings on the surface of nuggets reduced oil uptake and moisture loss of fried samples decreased by 33.21% and 29.64%, respectively. Antioxidant activity tests showed that oxygen radical absorbance capacity (ORAC) and DPPH radicals scavenging activity of carvacrol microcapsules were 152.23 ± 4.11 µmol TE/g, and 51.09 ± 3.32%, respectively. Investigation of primary and secondary oxidation products in the fried nugget samples showed that the peroxide value and thiobarbituric acid levels in control samples were 7.43 meq peroxide/kg and 1.35 mg MDA/kg, respectively. The results of this study showed that the highest reduction in PV and TBA were 41.85 and 37.04% for the QSG-coated samples containing 1% carvacrol microcapsules. The color of QSG-coated samples did not change significantly compared to control samples, although their hardness was reduced compared to the control samples (p < 0.05). The results showed that the use of active edible coatings made from quince seed gum and containing carvacrol microcapsules did not show any negative effects on the sensory properties of nuggets.

Characterization of Fungi Associated with Olive Fruit Rot and Olive Oil Degradation in Crete, Southern Greece.

In November 2019, a severe outbreak of fruit rot was observed in olive orchards in Crete, southern Greece. Symptoms appeared primarily on fruits and stalks, resembling those caused by anthracnose. Typical symptoms were fruit rot, shrinkage, and mummification, associated commonly with stalk discoloration and fruit drop. Disease incidence was estimated at up to 100% in some cases, and an unprecedented increase in olive oil acidity reaching up to 8% (percentage of oleic acid) in severely affected olive groves was recorded. Thirty-two olive groves were then surveyed, and samples of fruit, stalk, leaf, and shoot were collected. Visual, stereoscopic, and microscopic observations revealed several fungi belonging to the genera Alternaria, Botryosphaeria, Capnodium, Colletotrichum, Fusarium, and Pseudocercospora. Fungal infection in fruits was commonly associated with concomitant infestation by the olive fruit fly Bactrocera oleae along with increased air temperature and relative humidity conditions that prevailed in October and November 2019. Twenty representative fungal strains isolated from symptomatic fruits and stalks were characterized by morphological, physiological, and molecular analyses. By internal transcribed spacer regions of ribosomal DNA region and translation elongation factor 1-α gene sequencing analysis, these isolates were identified as Alternaria spp., A. infectoria, Botryosphaeria dothidea, Colletotrichum boninense sensu lato, Fusarium lateritium, F. solani species complex and Stemphylium amaranthi. Pathogenicity tests on punctured fruits revealed that all isolates were pathogenic; however, F. solani isolates along with B. dothidea were the most virulent, and wounds were necessary for efficient fungal infection. Moreover, as few as 10 spores of F. solani were sufficient to cause significant infection in punctured fruits. F. solani was also capable of infecting olive fruits in the presence of B. oleae, with no additional wounding, in artificial inoculation experiments. Moreover, it was capable of colonizing and affecting olive blossoms. Further analyses of olive oil extracted from fruits artificially inoculated with F. solani indicated a significant increase in oil acidity, K232, K270, and peroxide value, whereas total phenol content was significantly decreased. To the best of our knowledge, this is the first report of F. solani associated with olive fruit rot and olive oil degradation worldwide.

Improving Prediction of Peroxide Value of Edible Oils Using Regularized Regression Models.

We present four unique prediction techniques, combined with multiple data pre-processing methods, utilizing a wide range of both oil types and oil peroxide values (PV) as well as incorporating natural aging for peroxide creation. Samples were PV assayed using a standard starch titration method, AOCS Method Cd 8-53, and used as a verified reference method for PV determination. Near-infrared (NIR) spectra were collected from each sample in two unique optical pathlengths (OPLs), 2 and 24 mm, then fused into a third distinct set. All three sets were used in partial least squares (PLS) regression, ridge regression, LASSO regression, and elastic net regression model calculation. While no individual regression model was established as the best, global models for each regression type and pre-processing method show good agreement between all regression types when performed in their optimal scenarios. Furthermore, small spectral window size boxcar averaging shows prediction accuracy improvements for edible oil PVs. Best-performing models for each regression type are: PLS regression, 25 point boxcar window fused OPL spectral information RMSEP = 2.50; ridge regression, 5 point boxcar window, 24 mm OPL, RMSEP = 2.20; LASSO raw spectral information, 24 mm OPL, RMSEP = 1.80; and elastic net, 10 point boxcar window, 24 mm OPL, RMSEP = 1.91. The results show promising advancements in the development of a full global model for PV determination of edible oils.

Multi-sensor integration approach based on hyperspectral imaging and electronic nose for quantitation of fat and peroxide value of pork meat.

The study assessed the feasibility of merging data acquired from hyperspectral imaging (HSI) and electronic nose (e-nose) to develop a robust method for the rapid prediction of intramuscular fat (IMF) and peroxide value (PV) of pork meat affected by temperature and NaCl treatments. Multivariate calibration models for prediction of IMF and PV using median spectra features (MSF) and image texture features (ITF) from HSI data and mean signal values (MSV) from e-nose signals were established based on support vector machine regression (SVMR). Optimum wavelengths highly related to IMF and PV were selected from the MSF and ITF. Next, recurring optimum wavelengths from the two feature groups were manually obtained and merged to constitute "combined attribute features" (CAF) which yielded acceptable results with (Rc2 = 0.877, 0.891; RMSEC = 2.410, 1.109; Rp2 = 0.790, 0.858; RMSEP = 3.611, 2.013) respectively for IMF and PV. MSV yielded relatively low results with (Rc2 = 0.783, 0.877; RMSEC = 4.591, 0.653; Rp2 = 0.704, 0.797; RMSEP = 3.991, 0.760) respectively for IMF and PV. Finally, data fusion of CAF and MSV was performed which yielded relatively improved prediction results with (Rc2 = 0.936, 0.955; RMSEC = 1.209, 0.997; Rp2 = 0.895, 0.901; RMSEP = 2.099, 1.008) respectively for IMF and PV. The results obtained demonstrate that it is feasible to mutually integrate spectral and image features with volatile information to quantitatively monitor IMF and PV in processed pork meat. Graphical abstract.

[Change pattern and correlation analysis of macroscopic characteristics, active components and rancidness degrees of Armeniacae Semen Amarum in deterioration process].

To discuss the effect of deterioration on the quality of Armeniacae Semen Amarum by observing the changes of macroscopic characteristics, active components and rancidness degrees of Armeniacae Semen Amarum in deterioration process. The traditional macroscopic identification was used to observe, identify and classify the morphologic and organleptic characteristics of Armeniacae Semen Amarum. The contents of amygdalin and fatty oil(two representatives of active components) were detected by HPLC and general rule 0713 in Chinese Pharmacopoeia, respectively. Acid value and peroxide value of the samples were selected as the representative indices of different rancidness degrees, and the general rule 2303 was adopted as the method for quantitative analysis. Then principal component analysis(PCA), partial least square analysis discrimination analysis(PLS-DA) were further utilized to establish the discriminative models of samples with different rancidness degrees, and also to screen out the largest contribution factors. In sensory evaluation, Armeniacae Semen Amarum samples were divided into three groups: non-rancid, slightly-rancid, and noticeably-rancid. The color of seed coat, cotyledon and surface of noticeably-rancid samples was deepened, and the odor differed much from non-rancid samples. Average content of amygdalin and fatty oil in non-rancid samples was 4.12% and 67.77%, respectively, both meeting the requirements of Chinese Pharmacopoeia; and decreased to some extent in slightly-rancid samples. However, the content of amygdalin sharply dropped to 0.074% in noticeably-rancid samples. The acid value and peroxide value were increased significantly with the intensifying of the rancidness degree, from only 1.363 and 0.016 74 in non-rancid samples to 1.865 and 0.023 70 in slightly-rancid samples, even doubled in noticeably-rancid samples(2.167 and 0.033 82). The discriminative models established by PCA and PLS-DA could complete the task of distinguishing the non-rancid samples from noticeably-rancid ones. The contribution degree of amygdalin content as one of the input attributes of discriminative model was higher than 1. Rancidness affected the quality of Armeniacae Semen Amarum, resulting in appearance changes, decrease in content of active components, and increase in acid value and peroxide value. Obviously, noticeably-rancid samples were non-conforming to Chinese Pharmacopoeia and no longer suitable for medicinal use. Rancidness can significantly reduce the quality of Armeniacae Semen Amarum, and even could possibly produce toxicity, which should attach more attention.

Cholesterol removal by selected metal-organic frameworks as adsorbents.

The aim of this study was to investigate the cholesterol removal capacity of seven metal-organic frameworks (MOF) and to compare with active carbon as adsorbents, and with aqueous ß-cyclodextrine complexation removal technique. There were slight color differences in the oil samples after the treatments. The lowest free fatty acidities (0.13% and 0.13% linoleic acid) and peroxide values (21.07 and 23.50 meqO2/kg) were measured in aluminum-MOF (Al-MOF) and titanium-MOF (Ti-MOF) treated samples when compared to control sample (0.15%, and 27.62 meqO2/kg). Cholesterol reduction ratios of the Al-MOF treated sample (27.45%) and Ti-MOF treated sample (26.27%) were higher among all adsorbent treatments, but lower than that of the ß-cyclodextrine aqueous complexation technique (33.07%). Further experiments with Al-MOF and Ti-MOF showed that when adsorbent addition level increased to 3.0%, removed cholesterol content increased. Likewise, when treatment times extended to 180 min, more cholesterol was removed. But, the removed cholesterol contents at 100 °C and 30 °C treatment temperatures were lower than that of at 50 °C treatment temperature. Further experiments with butter and sheep tail tallow showed that Al-MOF was quite effective as an adsorbent to remove cholesterol. This study proves the great potential of MOF to remove cholesterol selectively from oil/fat by adsorption principle.

Effect of storage on the quality of processed palm oil collected from local milling points within Ile-Ife, Osun State, Nigeria.

The influence of storage practices on physicochemical and microbial changes in crude palm oil (CPO) from milling points in Ile-Ife, Nigeria were investigated. Freshly milled CPO samples were collected from four traditional milling points, dispensed in 150 mL portions in sterile bottles and stored under two different conditions (sunlight reflection and in the dark, both at room temperature) for 4 months. Samples were obtained periodically during the storage period for microbiological and physicochemical analysis following established methods. The aerobic mesophilic (2.16 × 106 cfu/mL) and Enteric bacterial (1.6 × 106 cfu/mL) counts of the fresh CPO samples decreased during storage with those exposed to sunlight reflections having very high significant difference (P < 0.00) compared to those stored in the dark at P ≤ 0.05. The bacterial isolates were identified as Bacillus pasteurii (29%), Staphylococcus aureus (22%), Enterobacter aerogenes (17%), Micrococcus sp. (12%), Escherichia coli (8%), Pseudomonas aeruginosa (7%) and Serratia marcescens (5%). Of the physicochemical parameters studied, moisture content (MC) reduced significantly from between 2.55 and 5.50% in fresh sample to between 0.1 and 0.5% at the end of storage while the free fatty acids (FFA) increased from between 0.5 and 1.0% to between 2.2 and 3.1% respectively. Storage under the influence of sunlight resulted in significant increase in iodine value of CPO from Mills 1, 2 and 4, indicating oxidative instability of the palm oil. It could be concluded that storage of freshly milled palm oil at room temperature (in the dark or exposure to sunlight) for a period of 4 months resulted in reduced bacterial load, decrease in MC and stable peroxide value and FFA.

Estimation of oxidative indices in the raw and roasted hazelnuts by accelerated shelf-life testing.

To estimate the oxidative stability of the raw and roasted hazelnuts, accelerated shelf-life testing (ASLT) was used at elevated temperatures (55, 65 and 75 °C) at water activity (aw) of 0.43. Chemical parameters, including peroxide value (PV), para-anisidine value, and total oxidation value were measured to estimate the oxidative stability of the samples using Arrhenius model. In addition, the samples were maintained for 8 months in a real condition at 20-30 °C (long-term shelf-life testing) for validating the results obtained from short-term ASLT. The maximum activation energy (Ea, 78.76 kJ/mol °K) and Q10 (1.871) was obtained for PV in raw hazelnuts, while the minimum Ea (53.36 kJ/mol °K) and Q10 (1.552) were recorded for PV in roasted hazelnuts, indicating the negative effect of roasting process on the oxidative stability of the samples. In order to validate the estimations, the values predicted by short-term ASLT for each oxidation index were plotted versus their corresponding values in actual storage. The results showed good correlation coefficients (R2 = 0.91-0.98), confirming the fitness of the Arrhenius model to predict the oxidative indices of the samples during normal storage.

Oxidation of fish oil supplements in Australia.

Fish oils oxidise readily, forming primary and secondary oxidation products, which may be harmful for humans. Some recent studies reported that fish oil supplements in Australasia are oxidised above acceptable international limits, however other studies reported low levels of oxidation. This study employed peroxide and p-anisidine values determination to measure primary and secondary oxidation of fish oils in the Australian market. Of 26 supplements tested, 38% exceeded the limit for primary oxidation, 25% exceeded the limit for secondary oxidation and 33% exceeded the limit for total oxidation, according to international recommendations. Four specially marketed supplements were found to deliver significantly lower amounts of fish oil per capsule (165 vs. 577 mg, p = .007), yet cost significantly more on a per gram basis ($2.97 vs $0.39, p < .001). However, there were no differences in any oxidative markers between regular supplements and the specially marketed products.

Effect of skimmed milk and vegetable powders on shelf stability of millet-based composite flour.

BACKGROUND: Millet porridge is a major complementary food used in Uganda but it is limited in protein and micronutrients such as zinc and beta-carotene. Addition of milk and vegetable powders are known to greatly improve the nutrient content of millet flour. However, there was limited information on the shelf stability of the resultant composite flour. This study aimed at assessing the effect of milk and vegetable powders on the shelf stability of millet-based composite flour. RESULTS: There was a general increase in the moisture content, peroxide value (PV), free fatty acids (FFA), thiobaturic acid (TBA) and total plate count (TPC) of both composite and millet flours over the eight weeks storage period. However, higher moisture content, PV, FFA, TBA and TPC values were recorded in the composite flour compared to millet flour (control) at each sampling interval. Sensory evaluation results revealed that panelists preferred porridges prepared from millet only compared to those from composite flour. The degree of liking of porridges from both composite and millet flours generally decreased over the storage period. However, both porridges were deemed as acceptable by the end of the storage period. The TPC also remained below 105 cfu g-1 which is the maximum limit recommended by the Uganda National Bureau of Standards (UNBS). CONCLUSION: The study findings indicated that the addition of milk and vegetable powders negatively affected the stability of the composite flour. We recommend further studies to stabilize the product during storage. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Modelling, characterization and quality analysis of heated oil using electric moment and chemical properties.

The effect of temperature (30-90 °C) on the electrical parameter: dielectric constant (εr) of Sunflower, Olive and Corn oil exposed to three cycles of heating to frying temperature (175 ± 5 °C) was studied to exhibit the quality analysis of oil. Dielectric constant of heated oil was measured using designed inter-digitated electrode capacitor at different frequency (10 kHz-5 MHz) and temperature (30-90 °C). Dielectric constant (εr) of oil samples increases with cycles of heating. Variation of dielectric constant with frequency was premeditated using quadratic equation and the dependency factor was observed to be R2 > 0.914. Chemical kinetic dielectric constant with temperature was studied using Arrhenius law and observed that activation energy increases with cycles of heating. Andrade's equation was also fitted with the variation of εr with temperature and the dependency factor (R2 between 0.978 to 0.999) was observed to be highly correlated. Experiential physical properties like density, refractive index and εr were significantly correlated with the pragmatic peroxide value. The observed relation between εr with chemical property divulges the suitability of measured dielectric constant in real time and continuous evaluation of edible oil quality analysis in food industry.

Effect of ultrasound dielectric pretreatment on the oxidation resistance of vacuum-fried apple chips.

BACKGROUND: In order to investigate the effect of ultrasound dielectric pretreatment on the oxidation resistance of vacuum-fried apple chips, apple slices were pretreated at ultrasonic powers of 150, 250 and 400 W for times of 10, 20 and 30 min before vacuum frying. The quality and oxidation resistance of fried apple were evaluated by testing the dielectric properties and comparing the moisture content, oil uptake, color, acid value (AV) and peroxide value (PV) of apple chips. RESULTS: Ultrasonic treatment significantly changed the dielectric properties of apple slices. Moisture and oil contents of apple chips decreased with increasing ultrasonic power and time. During storage, the color retention of fried apple chips processed by ultrasound was improved. AV and PV values of fried apple chips processed by ultrasound were lower, which improved their antioxidant properties. CONCLUSION: The results of the present study indicated that ultrasound dielectric pretreatment improved not only the quality of vacuum-fried apple chips but also their antioxidant properties. © 2018 Society of Chemical Industry.

Prediction of chemical composition and peroxide value in unground pet foods by near-infrared spectroscopy.

The massive development of the pet food industry in recent years has lead to the formulation of hundreds of canine and feline complete extruded foods with the objective of meeting both the needs of the animals and numerous demands from pet owners. In the meantime, highly variable raw material compositions and the industry's new production techniques oblige manufacturers to monitor all phases of the extrusion process closely in order to ensure the targeted composition and quality of the products. This study aimed at evaluating the potential of infrared technology (visible and near-infrared spectrophotometer; 570-1842 nm) in predicting the chemical composition and peroxide value (PV) of unground commercial extruded dog foods. Six hundred and forty-nine commercial extruded dog foods were collected. For each product, an unground aliquot was analysed by infrared instrument while a second aliquot was sent to a laboratory for proximate analysis and PV quantification. The wide range of extruded dog food typologies included in the study was responsible for the wide variability observed within each nutritional trait, especially crude fibre and ash. The mean value of the 208 pet foods sampled for PV quantification was 17.49 mEq O2 /kg fat (min 2.2 and max 94.10 mEq O2 /kg fat). The coefficients of determination in cross-validation of NIRS prediction models were 0.77, 0.97, 0.83, 0.86, 0.78 and 0.94 for moisture, crude protein, crude fat, crude fibre, ash and nitrogen-free extract (NFE) respectively. PV prediction was less precise, as demonstrated by the coefficient of determination in cross-validation (0.66). The results demonstrated the potential of NIRS in predicting chemical composition in unground samples, with lower accuracy for moisture and ash, while PV prediction models suggest use for screening purposes only.

[Secondary lipid oxidation products. Human health risks evaluation (Article 1)].

The first article of the series describes possible applications of both proton nuclear magnetic resonance spectroscopy (1Н NMR) and Fourier transform infrared spectroscopy (FTIR) in food lipid thermo-oxidation analysis. Thermo-oxidation process is a source of various oxidation products. Some of them are known to be toxic, such as oxidized α,ß-unsaturated aldehydes and epoxidized linoleic acid derivatives. Today we know that routine nonspecific methods in lipid oxidation analysis are not informative, may provide incorrect results and procedures are long and laborious. Therefore it might be useful to find more reliable, accurate and informative physic-chemical methods measuring food lipid oxidation status. This paper is devoted to the most widely used in lipid analysis spectroscopic methods such as 1Н NMR and FTIR. It has been shown that 1Н NMR and FTIR provide more information on the types, formation and degradation time of compounds formed than wet chemistry methods. 1Н NMR gives qualitative and quantitative information on degraded and newly formed compounds and FTIR is able to measure a lot of standard oxidation indices with high accuracy. Both of them allow us to trace any compounds' evolution in lipid matrices in real time. Mention is made of their advantages for routine laboratory analysis.