1,721,081 research outputs found
Cholesterol photosensitized oxidation products in foods systems
No full textLipid oxidation is one of the main chemical degradations occurring in biological and food systems and leads to the formation of compounds that are related to aging and various chronic and degenerative diseases. The extent of oxidation will depend on the presence of antioxidants/pro-oxidants, the unsaturation degree of fatty acids, and environmental conditions. Lipid oxidation can also affect other molecules such as cholesterol leading to formation of its oxidation products (COPs), which exert a strong impact on the lipid metabolism and are involved in various chronic and degenerative diseases and disturbance of cell functionality. Additionally, the formation of COPs can be particularly favored in the presence of light and photosensitizers. This work evaluated the light sensitized cholesterol oxidation in different matrixes (e.g. beef, pork, horse, turkey and sardine muscle). In the retail market, fresh slices of meat or fish are usually displayed in refrigerated vessels wrapped with plastic film and are exposed to a fluorescent light. Under these conditions, COPs can reach the 1.3% of oxidized cholesterol. In order to reduce the oxidative process, different strategies could be used (feeding the animals with antioxidants, or by spraying the muscle food with lipid- or water-soluble antioxidants before packaging). However, the combined use of alternative protective packaging, appropriate lighting conditions and modified atmosphere with low oxygen content, can efficiently prevent photoxidation without modifying the food product composition and sensory properties
Wheat bran: from by-product to new food products?
No full textThe agri-food sector generates significant quantities of by-products and waste, the disposal of which produces negative environmental and economic impacts. The adoption of an industrial symbiosis approach to transfer and share resources between dissimilar industries reflects recent European strategies on decoupling economic growth from environmental impacts.
The durum wheat bran was suplied by an Italian producer. Five different bran layers were selected, isolated according to their sieving mesh size during the flour milling process and identified with an increasing number (L1-L5) from the outter to the inner layer, respectively. From each layer, the lipid fraction was extracted by soxhlet procedure1, using petroleum ether (40-60 °C) for 6 h, and the humidity was determined by means of a gravimetric method. Main lipid classes (triacylglycerols (TAG), diacylglycerols (DAG), monoacylglycerols (MAG), free and esterified sterols, free fatty acids (FFA)) and total fatty acid (FA) composition2 of each lipid extract, were also determined.
The humidity content was higher (~ 15%) in L1 with respect to the other layers, showing the lowest amount in L5 (~ 14%). The lipid content ranged from 8% (expressed in dry basis) (L3) to 5% (L1, L4 and L5). The lipid matter was mainly constituted by FFA (89–94% of total fat), followed by total sterols (3.4–4.0% of total fat), DAG (1.5–4.0% of total fat), TAG (0.6–2.4% of total fat) and MAG (0.7–1.1% of total fat). In general, FFA decreased from the outer to the inner layers, whereas TAG showed the opposite trend; this could be ascribed to a lipolytic phenomena related to an on-going fermentation process. Total FA were mainly constituted by polyunsaturated fatty acids (PUFA; 53–58% of total FA), followed by monounsaturated fatty acids (MUFA; 21–24% of total FA) and saturated fatty acids (SFA; 17–20% of total FA). More than 50% of total FA was represented by linoleic acid (C18:2 n-6; 51–54%); oleic acid (C18:1 n-9) ranged from 19% (L1) to 22% (L5), while the palmitic acid (C16:0) content was about 17% of total FA without significant differences among bran layers.
This preliminary study demonstrated that by-products from durum wheat bran could represent a source of added-value edible oil. The extracted oil could be potentially used as a functional ingredient due to its high content of PUFA and low amount of SFA, with an important contribution of linoleic acid (essential fatty acid). However, to ensure its stability and the preservation of its nutritional and sensory characteristics, a shelf-life study of the functional bran oil is necessary
Thermal oxidation of cholesterol: preliminary evaluation of 2-methyl-6-heptanone and 3-methylbutanal as volatile oxidation markers
No full textCholesterol oxidation in food and model systems is usually monitored by evaluating cholesterol oxidation
products, but the analysis is time-consuming and expensive. Therefore, the determination of volatile
compounds deriving from cholesterol thermoxidation could be valuable to identify other possible oxidation
markers. Cholesterol alone and in the presence of a triacylglycerol mixture (tripalmitin, tristearin,
and triolein) were thermoxidized at 170 °C for 15 min. In both model systems, the total volatile compounds
increased three times when oxidation time rose from 5 to 15 min. The main classes of volatile
compounds were aldehydes, ketones, alcohols and hydrocarbons, displaying a similar behavior in both
systems. After 5 min of oxidation, 2-methyl-6-heptanone was the main volatile compound, followed
by 3-methylpentane, 2,3-dimethyl-1-pentene and 3-methylbutanal. To verify if 2-methyl-6-heptanone
could be used as volatile marker of cholesterol oxidation, data were compared with the total cholesterol
oxidation products content of each system. A significant correlation between total cholesterol oxidation
products content and 2-methyl-6-heptanone amount was found when cholesterol was oxidized alone
(r2 = 0.994) and in presence of triacylglycerols (r2 = 0.998). When egg yolk was thermoxidized at 80 °C
for 6 h, 3-methylbutanal was the volatile compound that better explained the oxidative trend in this food
system, showing a significant correlation with cholesterol oxidation rate (r = 0.91). In conclusion, 2-
methyl-6-heptanone and 3-methylbutanal could represent an easy and cheaper strategy for monitoring
cholesterol oxidation in model systems and food samples, respectively; however, a deeper investigation
on the amount and type of volatile compounds generated from cholesterol oxidation according to the
food matrix, should be carried out
Effects of Wheat Bran-Derived Alkylresorcinols on the Physical and Oxidative Stability of Oil-in-Water Emulsions as related to pH
Full text linkAlkylresorcinols (ARs), a homolog series of phenolipids naturally occurring in many by-products, can meet the high demand of the food industry for natural antioxidants. In this study, ARs (C17–C25) were isolated from wheat bran, and their antioxidant activity was tested in oil-in-water emulsions at pH 3.5 and pH 7.0 at two concentrations (15 and 30 mg/L of emulsion) during 14 days of storage at 35 °C. Results revealed that lipid oxidation was affected by both ARs concentration and pH of the emulsion. Indeed, when ARs were added, a significant suppression of hydroperoxides and aldehydes (hexanal and nonanal) formation with a consequent prolongation of their lag phases (5-fold) was observed at pH 3.5, while at pH 7.0 the lag phases were doubled. No influence of ARs on emulsion particle size was found. The present work demonstrated how ARs could represent sustainable and innovative natural antioxidants for emulsion-based food
Antioxidant properties of ferulic acid-based lipophenols in oil-in-water (O/ W) emulsions
Full text linkButyl ferulate (BF) and octyl ferulate (OF) were investigated to enhance oxidative stability of 1.0% vegetable oil-in-water (O/W) emulsions at pH 3.5 and 7.0 at different concentrations (5, 10, 15, 20, and 25 mg/L of emulsion). Particle size distribution, droplet surface charge, hydroperoxides (PV), hexanal and nonanal were monitored for 14 days at 35 °C. Higher concentrations of BF and OF generated smaller particles at pH 7.0 but not at pH 3.5. Control showed the highest negative surface charge (−58.38 ± 0.31 mV, pH 7.0) compared to BF and OF (−46.71 ± 0.06 mV at levels >0.10 mg/L). Both alkyl ferulates counteracted lipid oxidation, especially at pH 3.5, where PV decreased up to 96% compared to the control and delayed hexanal and nonanal formation. A low content of lipophenols allowed to achieve a tremendous shelf-life extension, demonstrating that BF and OF could be of great interest for food application
Effect of broccoli extract enriched diet on liver cholesterol oxidation in rats subjected to exhaustive exercise
No full textEffect of a Chitosan Coating Enriched with an Olive Leaf Extract on the Characteristics of Pork Burgers
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