S-sulfonate contents in raw and cooked meat products

S-Sulfonates (R-S-SO3-) are compounds formed by the reaction between the sulfites added to foodstuffs and the disulfide bonds of cystine, peptides, and proteins. The content of S-sulfonates has been determined in raw sausages and burgers (n = 62). The range of variation in the contents of the determined S-sulfonates is very wide and varies between 47 and 267 microg of SO2/g. The degree of formation of S-sulfonates with regard to the determined sulfite (total SO2 + S-sulfonates) is similar in all of the samples and does not seem to be conditioned by the meat compound (chicken or beef) or by the process of elaboration or type of product (burgers or sausages). In grilled burgers (n = 20) significant losses are produced in the levels of the additive in any of its forms. The value for the S-sulfonates is 31 +/- 9.8%, 29 +/- 6.6% corresponding to the free sulfite and a very similar percentage to the total sulfite (free + reversibly bound) 28 +/- 6.7%. It is possible that during the cooking process cleavages of some bound compounds occur, releasing SO2 and reacting to form new adducts.     

Dietary exposure of Canadians to perfluorinated carboxylates and perfluorooctane sulfonate via consumption of meat, fish, fast foods, and food items prepared in their packaging

Human exposure to perfluorinated compounds is a worldwide phenomenon; however, routes of human exposure to these compounds have not been well-characterized. Fifty-four solid food composite samples collected as part of the Canadian Total Diet Study (TDS) were analyzed for perfluorocarboxylates and perfluorooctanesulfonate (PFOS) using a methanol extraction liquid chromatography tandem mass spectrometry method. Foods analyzed included fish and seafood, meat, poultry, frozen entrées, fast food, and microwave popcorn collected from 1992 to 2004 and prepared as for consumption. Nine composites contained detectable levels of perfluorinated compounds-four meat-containing, three fish and shellfish, one fast food, and one microwave popcorn. PFOS and perfluorooctanoate (PFOA) were detected the most frequently; concentrations ranged from 0.5 to 4.5 ng/g. The average dietary intake of total perfluorocarboxylates and PFOS for Canadians was estimated to be 250 ng/day, using results from the 2004 TDS composites. A comparison with intakes of perfluorocarboxylates and PFOS via other routes (air, water, dust, treated carpeting, and apparel) suggested that diet is an important source of these compounds. There was a substantial margin of exposure between the toxicological points of reference and the magnitude of dietary intake of perfluorinated compounds for Canadians >/= 12 years old.     

Near-infrared reflectance spectroscopy enables the fast and accurate prediction of the essential amino acid contents in soy, rapeseed meal, sunflower meal, peas, fishmeal, meat meal products, and poultry meal

Near-infrared reflectance spectroscopy (NIRS) calibrations were developed to enable the accurate and fast prediction of the total contents of methionine, cystine, lysine, threonine, tryptophan, and other essential amino acids, protein, and moisture in the most important protein-rich feed ingredients. More than 1000 samples of global origin collected over four years were analyzed on amino acids following the official methods of the United States and the European Union. Detailed data and graphics are given to characterize the obtained calibration equations. NIRS was validated with independent samples for soy and meat meal products and compared to the amino acid predictions using linear crude protein regressions. With a few exceptions, validation showed that 85-98% of the amino acid variance in the samples could be explained using NIRS. NIRS predictions compared to reference results agree excellently, with relative mean deviations below 5%. Especially for meat and poultry meals, NIRS can predict amino acids much better than crude protein regressions. By enabling the amino acid analysis of many samples to be completed in a short time, NIRS can improve the accuracy of feed formulation and thus the quality and production costs of mixed feeds.     

Phytoestrogen content of foods of animal origin: dairy products, eggs, meat, fish, and seafood

Dietary phytoestrogens may be involved in the occurrence of chronic diseases. Reliable information on the phytoestrogen content in foods is required to assess dietary exposure and disease risk in epidemiological studies. However, existing analyses have focused on only one class of these compounds in plant-based foods, and there is only little information on foods of animal origin, leading to an underestimation of intake. This is the first comprehensive study of phytoestrogen content in animal food. We have determined the phytoestrogen content (isoflavones: biochanin A, daidzein, formononetin, genistein, and glycitein; lignans: secoisolariciresinol and matairesinol; coumestrol; equol; enterolactone; and enterodiol) in 115 foods of animal origin (including milk and milk-products, eggs, meat, fish, and seafood) and vegetarian substitutes using liquid chromatography-mass spectrometry (LC-MS) with (13)C-labeled internal standards. Phytoestrogens were detected in all foods analyzed; the average content was 20 microg/100 g of wet weight (isoflavones, 6 microg/100 g; lignans, 6 microg/100 g; equol, 3 microg/100 g; and enterolignans, 6 microg/100 g). In infant soy formula, 19 221 microg/100 g phytoestrogens were detected (compared to 59 microg/100 g in non-soy formula). Our study shows that all foods analyzed contained phytoestrogens and most foods (except for fish, seafood, and butter) contained mammalian phytoestrogens (enterolignans and equol). This is the first comprehensive study of phytoestrogen content of foods of animal origin and will allow for a more accurate estimation of exposure to dietary phytoestrogens.     

Heavy metal, total arsenic, and inorganic arsenic contents of algae food products

The total arsenic, inorganic arsenic, lead, cadmium, and mercury contents of 18 algae food products currently on sale in Spain were determined. The suitability of the analytical methodologies for this type of matrix was confirmed by evaluating their analytical characteristics. The concentration ranges found for each contaminant, expressed in milligrams per kilogram of dry weight, were as follows: total arsenic, 2.3-141; inorganic arsenic, 0.15-88; lead, < 0.05-1.33; cadmium, 0.03-1.9; and mercury, 0.004-0.04. There is currently no legislation in Spain regarding contaminants in algae food products, but some of the samples analyzed revealed Cd and inorganic As levels higher than those permitted by legislation in other countries. Given the high concentrations of inorganic As found in Hizikia fusiforme, a daily consumption of 1.7 g of the product would reach the Provisional Tolerable Weekly Intake recommended by the WHO for an average body weight of 68 kg. A more comprehensive study of the contents and toxicological implications of the inorganic As present in the algae food products currently sold in Spain may be necessary, which might then be the basis for the introduction of specific sales restrictions.     

Contribution of the microbial and meat endogenous enzymes to the free amino acid and amine contents of dry fermented sausages.

The role of the starter culture and meat endogenous enzymes on the free amino acid and amine contents of dry fermented sausages was studied. Five batches of sausages were prepared. The control batch was manufactured with aseptic ingredients without microbial inoculation. The other four experimental batches were manufactured with aseptic ingredients inoculated with Lactobacillus plantarum 4045 or Micrococcus-12 or L. plantarum 4045 and Micrococcus-12 or L. plantarum 4045 and Staphylococcus sp. Their effects on pH, a(w), myofibrillar proteins, and free amino acid and amine contents were studied. Sausages inoculated only with L. plantarum 4045 or with this starter combined with a Micrococcaceae had the lowest pH as a result of carbohydrate fermentation. In all batches similar patterns were observed for myofibrillar proteins and free amino acids which could indicate that meat endogenous proteases play an important role in proteolytic phenomena. No changes were observed in the amine fraction, indicating that the strains used as starter cultures did not show amino acid decarboxylase activity.     

Total and reactive lysine contents in selected cereal-based food products

The aim of the study was to determine and compare reactive and total lysine contents in a range of breakfast cereal products. Crude fiber, fat, ash, and crude protein contents of 20 breakfast cereal products ranged from 4 to 38, 14 to 144, 7 to 32, and 52 to 253 g/kg, respectively. The concentrations of glutamic acid (18.7-32.1 g/100 g protein) and proline (4.7-10.8 g/100 g protein) were high while those of the amino acids methionine (1.2-2.0 g/100 g protein) and histidine (1.2-3.3 g/100 g protein) were relatively low. There was a strong relationship between reactive lysine determined using the guanidination and fluorodinitrobenzene methods (R = 0.99). The total lysine content, determined after conventional acid hydrolysis, ranged from 0.8 to 3.7 g/100 g protein, while the reactive lysine content (guanidination) ranged from 0.4 to 2.8 g/100 g protein. Reactive lysine was 20-54% lower than total lysine in the cereal products. The large differences between total and reactive lysine suggest a considerable loss of lysine in the breakfast cereals tested.     

Past food habit change is related to obesity, lifestyle and socio-economic factors in the Malmo Diet and Cancer Cohort

OBJECTIVES: To examine if obesity status and socio-economic and lifestyle factors are associated with self-reported past food habit change, and also whether the level of obesity depends on the reason for change. DESIGN: Cross-sectional analysis within the Malmo Diet and Cancer (MDC) study using data from the baseline examination and the extensive socio-economic and lifestyle questionnaire including questions of past food habit change. The risk of having changed food habits in the past was examined using logistic regression. Mean differences in obesity status across categories of reasons for past food habit change were examined using analysis of variance. SETTING: Malm?, the third largest city in Sweden. SUBJECTS: A sub-sample (15 282 women and 9867 men) from the MDC cohort recruited from 1992 to 1996. RESULTS: Individuals with body mass index (BMI) >30 kg m(-2) had an increased risk of having reported past food habit change compared with individuals with BMI <25 kg m(-2) (odds ratio (OR) = 1.63, 95% confidence interval (CI) = 1.48-1.83 for women; OR = 1.53, 95% CI = 1.32-1.76 for men). The highest level of obesity was observed among individuals who had changed their diet due to reasons related to the metabolic syndrome. Changers were more likely to be highly educated and to live alone, be retired, ex-smokers and non-drinkers at baseline. CONCLUSIONS: Because past food habit change is related to obesity and other lifestyle and socio-economic factors, a complex confounding situation may exist that could seriously influence observed relationships between diet and disease. Studies need to collect information on past food habit change and take this information into account in the analysis and when interpreting study outcomes.     

Bacteria in the food,gut contents and faeces of the litter-feeding millipede glomeris marginata (villers)

Bacteria from the food leaves and faeces of millipedes maintained in group cultures (12 animals) for 24 h were counted. Dilution plating and direct observation both showed significant increases in bacterial populations (10–100 fold) after passage through the gut. In cultures of single animals the increases were primarily the result of rapid growth in the midgut, though there was some evidence of further proliferation in the hindgut and faeces. The ratio of viable counts to direct counts was lower in litter than in the gut and faeces, suggesting that the gut environment enhanced bacterial growth and viability. Correlation between counts from guts and food leaves further indicated that the growth response was by the litter microflora and not indigenous gut symbionts.     

Impact of food disinfection on beneficial biothiol contents in strawberry

In this study, the impact of four food disinfectants including hydrogen peroxide, free chlorine, and gaseous- and aqueous-phase ozone with industrial doses on the concentration of biothiol compounds gamma-glutamylcysteinylglycine (GSH) and cystein (CYS) in strawberry was investigated for 1, 5, 15, 30, and 60 or 120 min. Additionally, the amount of oxidized glutathione (GSSG) was analyzed for calculation of the GSH/GSSG ratio as an indicator of oxidative stress. After this treatment, thiol contents of strawberry samples were examined using high-performance liquid chromatography (HPLC) technique. According to the results of measurements, free chlorine treatment for only 60 min significantly decreased CYS content in strawberry (p < 0.05). A significant decline in the GSH/GSSG ratio was also observed when H2O2 was applied for all time intervals except for 1 min (p < 0.05). However, aqueous-phase ozone treatment did not significantly affect the thiol levels (p < 0.05). In conclusion, this study may provide optimum disinfection methods for strawberry to minimize loss of beneficial biothiols.     

Impact of food disinfection on beneficial biothiol contents in vegetables

In this work we investigated the impact of food disinfection on the beneficial biothiol contents in a suite of vegetables consumed daily, including spinach, green bean, asparagus, cucumber, and red pepper. Four disinfection technologies commonly studied and/or used in food processing and preservation, including hydrogen peroxide, free chlorine, and gaseous- and aqueous-phase ozone, were examined with common dosages and contact times. Results indicate that the common disinfection technologies may result in significant loss of beneficial biothiols in vegetables which are essentially important to human health. For example, as much as 70% of biothiols were lost when spinach was treated with hydrogen peroxide (5.0 wt %) for 30 min. Approximately 48-54% of biothiols were destroyed by free chlorine and gaseous- and aqueous-phase ozone under typical contacting conditions. In red pepper, about 60-71% of reduced glutathione was oxidized by the disinfectants. The potential decrease in biothiols during disinfection was dependent upon the biothiol type, the disinfectant, and the vegetable. The effectiveness of total bacterial inactivation by the four disinfection technologies was concurrently evaluated. Results show that free chlorine is most effective, achieving disinfection efficiencies of greater than 4 log for all study vegetables. This study may provide important information for the food industry to design optimum contacting methods for vegetables to simultaneously achieve sufficient bacterial disinfection while minimizing loss of beneficial biothiols.     

猪肉通电加热解冻及快餐肠制作工艺研究

该文以市售猪肉为主要的研究对象,采用电加热加工手段,研究解冻和快餐肠制作工艺,结果表明:冻肉通电加热过程中采用0.4%的食盐水作介质,可以加快解冻过程,并很好的保持了肉的品质;猪肉在通电加热过程中电导率的变化与电场方向及肉的结构有关;在电压对肉糜加热速率和电导率的影响中,在一定范围内,电压越高,肉糜加热速率越快;通电加热制作快餐肠最佳工艺条件为:在食盐含量为0.4%、电压为100V条件下通电加热5min。     

精料补充料中肉骨粉含量的近红外光谱检测

为了保证饲料安全,精料补充料中肉骨粉的检测是十分必要的。该文探讨了精料补充料中肉骨粉含量的近红外光谱分析方法,123个样品作为校正集,采用偏最小二乘法(PLS),分别对光谱进行散射校正和卷积平滑、一阶微分、二阶微分预处理建立校正模型,以最大的决定系数(R²)和最小的标准差(RMSEC)为选择依据,通过比较,以多元散射校正和卷积平滑处理与二阶微分相结合的处理效果最好,其预测值与测量值的决定系数(R²)和标准差(RMSEC)分别为0.9751和0.437。34个样品作为检验集进行外部验证,决定系数(r²)和标准差(RMSEP)分别为0.9749和0.420,平均绝对误差和相对误差分别为0.326和13.89％。结果表明,利用近红外分析技术可以检测精料补充料中肉骨粉的含量。     

Associations between parental report of the home food environment and adolescent intakes of fruits, vegetables and dairy foods

OBJECTIVE: This study examines parental report of household food availability, parent dietary intake and associations with adolescent intakes of fruits, vegetables and dairy foods. DESIGN: Cross-sectional study. Adolescents completed the Project EAT survey and the Youth Adolescent Food Frequency Questionnaire at school. Parents of adolescents were interviewed by telephone about the home food environment, eating habits and weight-related behaviours. General linear modelling was used to compare dietary intakes of adolescents across different levels of household food availability and parental intakes. SUBJECTS/SETTING: The study sample included 902 adolescents and their parent or guardian. RESULTS: Many parents were not consuming the minimum number of daily recommended fruit (44.5%), vegetable (69.9%) or dairy (46.9%) servings. While most parents reported that fruits and vegetables were available at home (90.3%) and vegetables were usually served at dinner (87.0%), fewer parents reported milk was served at meals (66.6%). Soft drinks were usually available at home (56.8%). Among girls, household availability was positively associated with fruit and vegetable intake (ttrend=2.70, P<0.01) and soft drink availability was inversely associated with dairy intake (ttrend=2.08, P=0.04). Among boys, serving milk at meals was positively associated with dairy intake (ttrend=3.65, P<0.01). Parental intakes were positively associated with dairy intake for boys (ttrend=2.04, P=0.04), and with dairy (ttrend=2.43, P=0.01), vegetable (ttrend=3.72, P<0.01) and fruit (ttrend=3.17, P<0.01) intakes for girls. CONCLUSIONS/APPLICATIONS: Interventions designed to help adolescents improve consumption of fruits, vegetables and dairy foods may be enhanced by including a parental component aimed at increasing household availability and parents' intake of healthful food choices.     

维生素A对高脂饲喂小鼠脂肪降解及胆固醇清除的影响

研究维生素A（VA）对高脂饲喂条件下小鼠（Mus musculus）肝脏中脂肪降解相关基因mRNA表达和血清胆固醇含量的影响,探索其是否可促进小鼠体内脂肪降解及胆固醇清除。通过石蜡切片观察高脂饲喂小鼠肝脏中脂滴分布;利用Real-timePCR检测小鼠肝脏各相关基因mRNA表达量;采用试剂盒测定血清胆固醇含量。结果显示,第1～3天VA处理组与对照组小鼠体重差异不显著（P〉0.05）;第4、9、27天,VA处理组小鼠体重显著低于对照组（P〈0.05）;VA处理组皮下脂肪（0.1890&#177;0.0056）g与腹膜下脂肪垫（0.3862&#177;0.0053）g重量极显著低于对照组（0.2620&#177;0.0020）g与（0.4867&#177;0.0052）g重量（P〈0.01）;切片观察肝脏充脂细胞数量明显减少;VA处理组小鼠肝脏清道夫受体B族Ⅰ型（（SR-BⅠ）、激素敏感脂酶（HSL）基因mRNA表达量极显著高于对照组（P〈0.01）;过氧化物酶体增生物激活受体γ（PPARγ）、固醇调节元件结合蛋白-1c（SREBP-1c）基因表达量显著低于对照组（P〈0.05）;甘油三酯水解酶（TGH）基因表达量显著高于对照组（P〈0.05）;VA处理组小鼠血清胆固醇（CHO）及高密度脂蛋白胆固醇（HDL-C）浓度均极显著低于对照组CHO及HDL-C浓度（P〈0.01）。说明VA可通过SR-BⅠ促进脂肪降解和血清中HDL-C清除。     

Variation of hydrogen, carbon, nitrogen, and oxygen stable isotope ratios in an American diet: fast food meals

The stable isotopes of hydrogen, carbon, nitrogen, and oxygen provide insights into a heterotrophic organism's diet and geographic origin. Although the contribution of food delta (2)H and delta (18)O to the final tissue signal will not vary for constrained diets, it will for animals eating varied diets, that is, humans. This study surveyed the isotopic range in one portion of the American diet, fast food meals. Hamburger patties, buns, and French fries from national chain restaurants across the United States and from local restaurants (Salt Lake City, UT, and Charleston, SC) were analyzed for delta (2)H, delta (13)C, delta (15)N (patties only) and delta (18)O values. Patties and buns from local Utah restaurants were more depleted for delta (2)H, delta (13)C, and delta (18)O values than samples from other restaurants. There were no significant differences in delta values among French fries. All three components of the fast food meal displayed significant linear delta (2)H versus delta (18)O relationships (delta (2)H = 7.8delta (18)O - 237 per thousand, delta (2)H = 5.9delta (18)O - 258 per thousand, and delta (2)H = 3.3delta (18)O - 231 per thousand for patties, buns, and fries, respectively). The findings show that significant predictable variation exists in the stable isotopic composition of fast food meals. It is proposed that the variation in delta (13)C values of hamburger (beef) patties is indicative of differences in cattle-rearing practices, whereas delta (2)H and delta (18)O values are evidence of geographic variation in food sources. Although the patterns support the concept of a "continental" supermarket diet, there appears to be a strong regional component within the diet.     

Milk and dairy products in the 21st century. Prepared for the 50th anniversary of the journal of agricultural and food chemistry

Dairying into the 21st century will largely continue with the trends seen in the past few decades, although there is always the possibility of an unlikely but disruptive event. The politics of globalization will potentially be important in freeing up global trade in dairy products. Production on the farm will become increasingly efficient, resulting in continuing price benefits to the consumer. At the same time, increasing attention will be paid by the consumer, producer, and manufacturer to safety and quality issues. Environmental concerns will increase in importance, and the issue of methane production may be important for the industry over the next two decades. It is unlikely that genetically modified milk will be introduced soon, even if public acceptance ceases to be an issue; however, the use of genetic markers for accelerated genetic improvement of cows will have rapidly increasing importance. Despite increasing pressure from nonmilk alternatives, milk and dairy will still be the best sources of nutrition for the young and for traditional dairy products. Consumer concerns will be of overriding importance for the industry, and the safety of dairy foods must become absolute. Recent advances in the chemical, physical, and information sciences and technologies will be utilized to gain greater understanding of the increasingly complex food systems and to support the consumer objectives.