Effect of cooking and drying on the thermal conductivity of rice

The transient line source technique was used to determine the thermal conductivity of rice during cooking and drying of cooked rice. A temperature range of 50‐70°C, moisture content of 10‐70% (wet basis), bulk (packing) density range of 500‐850 kg/m³ and porosity range of 0.265‐0.7 were studied. Thermal conductivity increased with increasing temperature, moisture content and bulk density, and the values were in the range 0.082‐0.543 W/m °C. This value is comparable with the literature values for granular and gelatinized starch. The data on the effect of phase change due to gelatinization have also been included. The experimental values were statistically analyzed and empirical polynomial equations were developed in terms of temperature, bulk density, porosity and moisture content of rice during cooking and drying the cooked material.     

Risk assessment of dietary exposure to phytosterol oxidation products from baked food in China

Phytosterols are nutritional phytochemicals that may undergo oxidation and be transformed into phytosterol oxidation products (POPs), thus inducing pathological and toxic effects. This work investigated four main phytosterols and 28 POPs in 104 kinds of commercial baked food by using GC-MS. The dietary exposure and hazard index values (HI) associated with POPs from baked food consumption in China were estimated by using Monte Carlo simulation. Concentrations of the total phytosterols were between 3.39 and 209.80 μg/g. The total concentrations of POPs, including 5α,6α/5β,6β-epoxysterols, 7-ketosterol, 7α/7β-hydroxysterols, 6-hydroxysterols, and triols, ranged from 0.37 to 27.81 μg/g. The median dietary exposure of POP contents in baked food for four age groups in China were 10.91 (children), 6.20 (adolescents), 3.63 (adults), and 3.40 (seniors) mg/(kg×day). Risk assessment of median HI with respect to POPs indicated no risk (HI <1) for people in adolescents, adults, and seniors in the country area of China, while a risk (1 < HI < 10) would refer to the baked food consumption of people in urban area and children in country area of China. Sensitivity and uncertainty analysis showed that the most significant variables for each age group in China were POP concentration, body weight, and ingestion rate.     

Lipid classes,fatty acids and bioactive lipids of genetically modified potato Spunta with Cry V gene

The objective of this study was to evaluate the lipid bioactive compounds distribution of genetically modified potato (GMP) Spunta compared to that of non-genetically modified potato (NGMP) Spunta. In two lines of GMP Spunta (G2 and G3) as well as in control cultivar the levels and composition of the lipids extracted from the mature tubers were characterised in terms of its fatty acid, sterol, tocopherol distribution as well as lipid classes and unsaponifiables levels. Column chromatography (CC), gas chromatography (GC), thin layer chromatography (TLC) and liquid chromatography (LC) techniques were performed to analyse lipids. NGMP and GMP lines (G2 and G3) were found to contain 0.59%, 0.75% and 0.72% of total lipids (TL), respectively. Amongst TL present in NGMP, the level of phospholipids was the highest (53% of TL), followed by neutral lipids (24% of TL) and glycolipids (23% of TL), respectively. Significant decrease in phospholipids levels was measured in GMP G2 and G3 (from 53% of TL in NGMP to 40% of TL in GMP). Neutral lipids were measured in higher amounts in GMP G2 and G3 (400 and 390 g/kg TL, respectively). Glycolipids were measured in the highest amounts in NGMP (230 g/kg TL) followed be GMP G3 (200 g/kg) and GMP G2, respectively. The predominant phospholipid subclasses in NGMP and GMP Spunta were phosphatidylcholine (43–46%) followed by phosphatidylethanolamine (31–33%). The content of oleic and linoleic acids, which were the main fatty acids of potato tubers, came to 64.5% of all acids. TL from NGMP additionally contained higher amounts of palmitic and stearic, while polyunsaturated fatty acids were found in higher amounts in GMP (31.9% of total FAME). GMP G3 contained the highest amounts of total sterols (29 g/kg oil), followed be GMP G2 (26 g/kg oil) and NGMP, respectively. β-Sitosterol was the ST marker and comprised 43.1–43.7% of total sterols, wherein the next major components were campesterol and △5-avenasterol. α-Tocopherol was the main identified compound (77.5–80% of total tocopherols) in GMP and NGMP Spunta followed by β-tocopherol. Detailed knowledge on the composition of lipids in potato Spunta, in consideration of potential utilisation, is of major importance.     

Determination of phytosterol oxides in some food products by using an optimized transesterification method

An increased intake of phytosterols (PS), as well as new products launched on the market enriched with PS and phytostanols, increases the demands for improved analytical techniques. In the present study, a method for the determination of phytosterol oxidation products (POP) was evaluated and optimized. The method included transesterification, enrichment with amino SPE cartridges and quantification by GC. The methodology was evaluated with authentic samples of sito-, campe- and stigma-sterol oxidation products and the linearity and recovery for some POP were >0.95 and 80–120%, respectively. The lowest spiking level determined was 0.5 μg and lower levels could be quantified. In addition, the formation of POP during thermal oxidation of vegetable oils at 180 °C for 0–2 h was studied and increased levels were observed. A commercially available PS ester-enriched margarine was also included in the investigation and the level of POP was 12 μg/g of spread.     

Phytosterol oxidation products in enriched foods: Occurrence,exposure, and biological effects

Hypercholesterolemia is an important risk factor for the development of cardiovascular diseases. Dietary intake of phytosterols/phytostanols and their fatty acid esters results in a reduction of the LDL and total plasma cholesterol levels. Therefore, these constituents are added to a broad spectrum of foods. As in the case of cholesterol, thermo‐oxidative treatment of phytosterols may result in the formation of phytosterol oxidation products (POPs), i.e. keto‐, hydroxy‐, and epoxy‐derivatives. This review summarizes and evaluates the current knowledge regarding POPs in the light of the potentially increasing dietary exposure to these constituents via the consumption of foods enriched with phytosterols/phytostanols and their esters. Data on the occurrence of POPs and approaches to assess the potential intake of POPs resulting from the consumption of enriched foods are described. The knowledge on the uptake of POPs and the presently available data on the impact of the consumption of enriched foods on the levels of POPs in humans are discussed. Biological effects of POPs, such as potential proatherogenic properties or the loss of the cholesterol‐lowering effects compared to nonoxidized phytosterols, are discussed. Finally, knowledge gaps are outlined and recommendations for further research needed for a safety assessment of POPs are presented.     

Fatty acids and cholesterol oxidation in salted and dried shrimp

The aim of this work was to evaluate the occurrence of cholesterol oxidation products and to analyze the lipidic profile in salted–dried shrimp. Fifty samples of salted–dried shrimp were evaluated, and the cholesterol oxides (7β-OH, 7α-OH, 7-Keto and 25-OH) were quantified by high-performance liquid chromatography. The cholesterol oxides: 7β-OH (34.63–72.56 μg/g), 7α-OH (5.02–12.12μg/g), 7-Keto (7.44–32.68 μg/g) and 25-OH (2.37–22.88 μg/g) were determined in all samples analyzed. Regarding to the total cholesterol content and the average thiobarbituric acid reactive substances (TBARS) content, the results ranged from 73.88 to 247.69 mg/100 g, and 0.02 to 1.30 mgMA/kg, respectively. The fatty acids profile was: 27.48% saturated, 43.90% monounsaturated and 28.61% polyunsaturated. The presence of cholesterol oxidation products and the values of TBARS indicate the degree of oxidation of this product, which was probably initiated by inadequate conditions of processing and storage.     

Cholesterol oxide, cholesterol, total lipid and fatty acid contents in processed meat products during storage

The effects of storage time on the formation of cholesterol oxides and on alterations in the fatty acid composition of processed meat products manufactured by Brazilian industries were investigated in this study. Cholesterol oxides and cholesterol were determined by HPLC using photodiode array and refractive index detectors. Samples of jerked beef, Italian-type salami, chicken mortadella and Chester mortadella were analysed at 30 day intervals starting at zero time, for 90 days for the mortadella and 120 days for the jerked beef and salami. The mortadellas were stored under refrigeration at 6 °C and the jerked beef and salami at room temperature, but protected from the light. No cholesterol oxides were formed during the storage time in any of the samples. The cholesterol content, the fatty acid composition and total lipid contents showed no significant differences during storage with the exception of the total lipid content of the jerked beef, which varied from 3.5 at zero time to 2.4 g/100 g after 120 days storage.     

The effect of wounding intensities on vitamins and antioxidant enhancement in potato products

The effect of wounding intensity on vitamins and antioxidant activities from potato were evaluated. Potatoes were submitted to five levels of wounding intensity (A/W) including the whole peeled potato (CK), slices, pies, shreds and chopped samples. The results showed that vitamins in potato products had different responses to the same wounding intensity. Wounding intensity significantly induced VB₁, VB₂, nicotinic acid and nicotinamide accumulation in potato products, all of which were higher than that of control at each wounding intensity. Slice cutting increased the content of VB₂, VB₅, VB₇ and VB₉ compared with the control. Shreds cutting increased the content of nicotinic acid, nicotinamide and VC compared with the control. Chopped samples significantly increased the content of VB₆, chlorogenic acid and coumaric acid. The wounding intensities also induced the accumulation of L-phenylalanin ammonia lyase (PAL) activity. Superoxide dismutase (SOD) and peroxidase (POD) activities of potato products decreased after treated by cutting process.     

Cholesterol oxidation products in irradiated raw meat with different packaging and storage time

The effect of irradiation and packaging conditions on the formation of cholesterol oxidation products (COPs) as well as lipid oxidation products was determined in raw turkey leg, beef, and pork loin meat during 7 days of storage. Ground turkey leg, beef, and pork loin muscles were prepared as patties. The patties were individually packaged either in oxygen-permeable or impermeable bags, irradiated at 0 or 4.5 kGy using a Linear Accelerator, and stored at 4°C. The COPs such as 7-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol were detected in fresh raw meats at 0 day at the level of 10.9 to 49.2 μg/g lipid. After 7 days of storage, other COPs such as epoxides, 20-hyroxycholesterol, and choletanetriol were formed in mainly aerobically packaged and irradiated raw meats. Packaging effect was more crucial on the cholesterol and lipid oxidation than irradiation. In aerobically packaged and irradiated meats, turkey leg muscles had higher COPs value than beef or pork did. COPs and thiobarbituric acid reactive substances (TBARS) values had a strongly positive correlation in turkey leg and pork. But, cholesterol oxidation in beef proceeded in irradiated and aerobically stored samples despite of its low level of TBARS value.     

Effect of irradiation and packaging conditions after cooking on the formation of cholesterol and lipid oxidation products in meats during storage

The effect of irradiation and packaging conditions on the content of cholesterol oxidation products (COPs) and lipid oxidation in cooked turkey, beef, and pork during storage was studied. Ground turkey leg, beef, and pork were cooked, packaged either in oxygen-permeable or oxygen-impermeable bags, and irradiated at 0 or 4.5 kGy. Lipid oxidation and COPs were determined after 0 and 7 days of storage at 4°C. Packaging of cooked meat was more important than irradiation in developing COPs and lipid oxidation in cooked meats during storage. 7-Hydroxycholesterol, 7β-hydroxycholesterol, β-epoxide, and 7-ketocholesterol were among the major COPs formed in cooked turkey, beef, and pork after storage, and their amounts increased dramatically during the 7-day storage in aerobic conditions. Irradiation had no significant effect on the amounts of any of the COPs found in cooked turkey and beef, but increased (P<0.05) the amounts of - plus 7β-hydroxycholesterol, β-epoxide, 7-ketocholesterol, and total COPs in aerobically packaged cooked pork. The amounts of COPs and lipid oxidation products (TBARS) closely related to the proportion of polyunsaturated fatty acids in meat. The results indicated that the composition of fats in meat is important on the oxidation rates of lipids and cholesterol, and packaging is far more important than irradiation in the formation of COPs and lipid oxidation in cooked meat.     

Effectiveness of rosemary essential oil as an inhibitor of lipid and protein oxidation: Contradictory effects in different types of frankfurters

The effect of increasing levels (150, 300 and 600ppm) of rosemary essential oil on lipid and protein oxidation and the increase of non-heme iron (NHI) content during refrigeration (+4°C/60 days) of frankfurters produced with tissues from Iberian pigs (IF) or white pigs (WF), was studied. Frankfurters with no added essential oil were used as controls. Iberian pigs were free-range reared and fed on acorns and pasture whereas white pigs (Large-white×Landrance) were intensively reared and fed on a mixed diet. Large differences were detected between types of frankfurters (Iberian vs white) in terms of fatty acid composition and tocopherols content due to the different feeding background of the animals. The effect of the addition of rosemary essential oil on the oxidative stability of frankfurters depended on the level of added essential oil and the characteristic of the frankfurter. The rosemary essential oil successfully inhibited the development of lipid and protein oxidation in IF with that antioxidant effect being more intense at higher concentrations of essential oil. In WF, 150ppm rosemary essential oil showed an antioxidant effect, significantly reducing the generation of lipid and protein oxidation products. At higher levels (300 and 600ppm) the essential oil had, in general, no effect on lipid oxidation while significantly enhanced the oxidation of proteins and the release of iron from myoglobin. The presence of certain amounts of tocopherols in the frankfurters could have influenced the activity displayed by the added essential oil leading to antioxidant or prooxidants effects though the different fatty acid composition and oxidative status between frankfurters could also have had an effect.     

Relation between types of packaging,frozen storage and grilling on cholesterol and fatty acids oxidation in Atlantic hake fillets (Merluccius hubbsi)

Two different commercial samples of frozen and packaged, in low and high-oxygen permeability packaging, Atlantic hake fillets were stored at −18 °C for 4 months and the intensity of lipid oxidation, as well as the formation of cholesterol oxidation products (COP), during storage and subsequent grilling were studied. Raw fillets at the initial time of storage showed low total COP levels, however, after 120 days of storage the concentrations were raised significantly, under both packed conditions. During freezing and subsequent grilling there was a significant decrease (p < 0.02) in the contents of the cholesterol and polyunsaturated fatty acids in all the hake samples. Correlations were found between the cholesterol and fatty acid parameters and cholesterol oxides formation during storage and heat treatment. The commercial frozen storage with a low-oxygen permeability packaging was more effective in preventing lipid oxidation than high-oxygen permeability packaging, with less accented cholesterol degradation as well as cholesterol oxides formation.     

Rats fed blended oils containing coconut oil with groundnut oil or olive oil showed an enhanced activity of hepatic antioxidant enzymes and a reduction in LDL oxidation

The effects of feeding Wistar rats with blended and interesterified oils of coconut (CO):groundnut (GNO) or CO:olive (OLO) on liver antioxidant enzyme activities and susceptibility of LDL to oxidation were studied. The hepatic lipid peroxidation (LPO) levels in the rats fed CO:GNO blend and interesterified oils were increased by 31% and 21%, when compared to the rats given CO. The superoxide dismutase activity was increased by 31% and 28%, and catalase (CAT) activity was increased by 37% and 39%, respectively, in rats given blends and interesterified oils of CO:GNO, as compared to those given CO. The activities of glutathione peroxidase (GPx) were increased by 17% and 20% in rats given CO:GNO blend and interesterified oils. Glutathione transferase (GST) level was also found to be increased by 26% and 31% after feeding blended and interesterified oils of CO:GNO, compared to those given CO. The LDL oxidation, which was elevated by feeding GNO, was found to be reduced by 10% and 14%, respectively, in the groups fed blended and interesterified oils of CO:GNO. Similarly, CO:OLO blended oils enhanced SOD, CAT, GPx and GST activities by 34%, 43%, 27% and 23%, respectively, compared to the rats given CO-containing diets. The corresponding increases in theses antioxidant enzyme activities when CO:OLO interesterified oils were fed to rats were 38%, 50%, 28% and 26%, respectively, when compared to rats given CO-containing diets. There was a significant reduction in hepatic LPO as well as oxidation of LDL, when blended and interesterified oils of CO:OLO were fed to rats. The results demonstrated that blended and interesterified oils of CO with GNO or OLO enhance hepatic antioxidant enzymes, decreased lipid peroxidation in liver and reduced the susceptibility of LDL to oxidation.     

Short communication: Effect of commercial or depurinized milk diet on plasma advanced oxidation protein products,cardiovascular markers,and bone marrow CD34 stem cell potential in rat experimental hyperuricemia

Cardiovascular repair and myocardial contractility may be improved by migration of bone marrow stem cells (BMSC) and their delivery to the site of injury, a process known as BMSC homing. The aim of our study was to examine the dietary effect of a newly patented depurinized milk (DP) that is almost free of uric acid and purine and pyrimidine compounds compared with a standard commercial 1.5% fat UHT milk diet or allopurinol therapy in rat experimental hyperuricemia. Bone marrow stem cell potential (BMCD34⁺, CD34-postive bone marrow cells), plasma oxidative stress parameters [advanced oxidation protein products, AOPP) and thiobarbituric acid reactive substances (TBARS)], myocardial damage markers [creatine phosphokinase (CPK), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH)], plasma cholesterol, and high-density lipoprotein cholesterol were investigated. The DP milk diet significantly increased the number of BMCD34⁺ stem cells compared with commercial UHT milk. Allopurinol given alone also increased the number of BMCD34⁺. Hyperuricemia caused a significant increase in all plasma enzyme markers for myocardial damage (CPK, LDH, and AST). A cardioprotective effect was achieved with allopurinol but almost equally with DP milk and more than with commercial milk. Regarding plasma AOPP, TBARS, and cholesterol levels, the most effective treatment was DP milk. In conclusion, the protective role of a milk diet on cardiovascular function may be enhanced through the new depurinized milk diet, which may improve cardiovascular system function via increased bone marrow stem cell regenerative potential, decreased plasma oxidative stress parameters, and decreased levels of myocardial damage markers and cholesterol. New dairy technology strategies focused on eliminating harmful milk compounds should be completely nontoxic. Novel milk products should be tested for their ability to improve tissue repair and function.     

ω‐3 in meat products: benefits and effects on lipid oxidative stability

Although ω‐3 intake has been associated with numerous health benefits, its addition to certain food matrices, and in particular meat products, may involve various technological barriers influencing the final quality of the products. Lipid oxidation must be highlighted due to the modification of both the sensory characteristics and the shelf‐life of meat products. In order to reduce the impact of chemical changes and promote oxidative stability, the use of natural antioxidants has gained ground owing to the health and safety advantages linked to its effectiveness at reducing lipid oxidation. Many natural compounds have also been successfully tested in animal feed, in order to protect the raw meat materials and reduce the risk of lipid oxidation in processed products. This review aims to address the challenges and advantages of the incorporation of ω‐3 fatty acids in raw meat materials and processed meat products, and to describe the use of different compounds to enhance lipid oxidative stability. © 2015 Society of Chemical Industry