Long‐chain fatty acid supplemented infant formula does not influence calcium and magnesium bioavailability in weanling rats

The influence of infant formula supplementation with long‐chain‐polyunsaturated fatty acids (LCPUFA) on calcium and magnesium bioavailability was assessed in rats. Two test diets containing a plain, unsupplemented (PF) or supplemented (SF) infant formula as the fat source and a control diet (C) were administered to weaning rats and food intake and body weight gain were monitored for 28 days. In order to assess calcium and magnesium bioavailability, during the last week faeces and urine were collected and apparent absorption and retention were calculated. Food intake and body weight showed no significant differences between PF and SF but were lower in both groups compared with C. Calcium and magnesium intake did not differ between PF and SF, although both parameters were lower compared with C. Calcium absorption efficiency in PF and SF was significantly higher than in C. However, both groups showed higher urinary calcium excretion and thus no differences were observed in calcium retention. Magnesium absorption efficiency was also significantly higher in PF and SF compared with C, but magnesium absorption was significantly lower in SF compared with PF and C. Nevertheless, urinary magnesium excretion and magnesium retention were similar in the three groups. The consumption of a diet containing an infant formula supplemented with LCPUFA compared with the plain formula does not affect calcium and magnesium bioavailability in rats. Copyright © 2005 Society of Chemical Industry     

In vitro intestinal absorption of amino acid mixtures extracted from codfish (Gadus morhua L.) salting wastewater

This study reports on the intestinal permeability of salt‐containing mixtures of amino acids extracted from codfish salting wastewater. Permeability was evaluated in vitro using the Caco‐2 cell line model; cell integrity during exposure to mixtures of amino acids was estimated by measuring the transepithelial electrical resistance (TEER). The effect of salt (NaCl) on the permeability and on the intestinal cell's integrity was also examined. Permeation rate (i.e. transport) was ≥95% for all amino acids except for creatine, for which it was 6%. Values for apparent permeability coefficients, P_app > 10^?5 cm s^?1, for mixture with isotonic concentration of NaCl suggest that amino acids are very likely to be absorbed in humans. Mixture with a hypertonic level of NaCl exerts a cytotoxic effect in intestinal cells resulting in a loss of epithelium integrity. Results show that isotonic mixture of amino acids extracted from codfish salting wastewater could be used in food, feed, cosmetic and pharmaceutical formulations. These applications could contribute to the fish industry sustainability.     

青海胡芦巴种子氨基酸含量分析及评价

为评价青海胡芦巴的品质,以2-[2-（7H-二苯并[a,g]咔唑）-乙基]氯甲酸酯（DBCEC-Cl）为衍生试剂,采用柱前衍生-高效液相色谱荧光检测法（HPLC-FLD）对胡芦巴种子中的18种氨基酸的含量进行了测定,并结合WHO/FAO氨基酸评分标准等多种方法对青海胡芦巴进行综合评价。结果发现,胡芦巴种子的必需氨基酸总量很高,几种必需氨基酸的比例均超过WHO/FAO标准模式,氨基酸比值系数分为75.54,EAAI指数为111.62。研究表明,胡芦巴种子氨基酸种类多,必需氨基酸含量高,组成合理均衡,有较高的研究价值和良好的开发利用前景。      

不同烹饪条件下食物中反式酸含量变化的研究

大量研究已经证明食物中的反式酸对人体健康有害,目前国外人们日常餐饮主要采用煎炸方式烹饪食物,而国内餐饮主要采用煎炒食物的烹饪操作,研究烹饪过程中反式酸含量的变化情况有着重要意义。采用煎炸鸡翅和薯条,煎炒土豆丝和肉丝的方法,来考察食物在烹饪过程中反式酸的变化情况。试验结果显示:煎炸完鸡翅后,鸡翅反式酸含量从起始的0.032 g/100 g变化到0.178 g/100 g(P<0.05)。煎炸完薯条后,薯条的反式酸含量从起始的0.019 g/100 g变化到0.269 g/100 g(P<0.05)。煎炒完土豆丝和肉丝后,食物反式酸含量由起始的0 g/100 g和0.017 g/100 g变化到0.037 g/100 g(P>0.05)和0.023 g/100 g(P>0.05)。上述试验结果说明煎炒后食物中反式酸的含量变化不显著,虽然煎炸后食物中反式酸的含量显著升高,但其反式酸的总量都小于0.30 g/100 g,均处于较低的水平。     

Microbiological and organoleptic characteristics of beef trim and ground beef treated with acetic acid, lactic acid, acidified sodium chlorite, or sterile water in a simulated commercial processing environment to reduce Escherichia coli O157:H7 and Salmonella

The objective of this study was to validate the effectiveness of acetic and lactic acids (2% and 5%), acidified sodium chlorite (1000 ppm), and sterile water in reducing Escherichia coli O157:H7 and Salmonella Typhimurium in inoculated beef trim in a simulated processing environment. Samples were collected to assess microbial characteristics at three processing points. Results from this study indicate that all treatments, including sterile water, reduced pathogen concentrations (P < 0.05) of both E. coli O157:H7 and Salmonella Typhimurium in ground beef up to 0.5 and 0.6 log by 24 h, respectively. In some cases, there were no significant differences between the antimicrobial treatments and the sterile water using this application method. Triangle sensory test results of non-inoculated beef indicated there were no differences (P < 0.05) in the means of correct responses between controls or antimicrobial treatments at 6 or 24 h. While interventions are important for beef trim, use of the interventions must be validated under industry conditions to ensure proper effectiveness.     

Influence of dietary phenolic acids on redox status of iron: Ferrous iron autoxidation and ferric iron reduction

We investigated the effect of dietary phenolic acids on the oxidation of Fe²⁺ caused by molecular oxygen. All phenolic acids bearing 3,4-dihydroxy (catechol) or 3,4,5-trihydroxy (galloyl) moiety formed chelates with ferric iron and significantly increased the rate of Fe²⁺ autoxidation. The carboxylate group and catechol substitution instead of galloyl moiety facilitated the ferrous ion oxidation more effectively. Caffeic acid and protocatechuic acid, the strongest accelerators of Fe²⁺ autoxidation, were able to facilitate autoxidation at concentrations lower than 1% of the initial amount of Fe²⁺. Therefore chelates of these catecholic acids with iron displayed ferroxidase-like activity. Conversely, when we started from ferric ions, catechols partially formed ferrous ions in the presence of ferrozine. Thus, catecholic acids formed stable chelates with iron, in which ferric ion is the dominant species, but the redox cycling of iron between Fe²⁺ and Fe³⁺ in chelates probably plays a crucial role in the catalysis of ferrous iron autoxidation. Interestingly, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid and vanillic (4-hydroxy-3-methoxybenzoic) acid protected ferrous ions from autoxidation as effectively as ascorbic acid and cysteine. These monophenolic acids, differently from ascorbic acid and cysteine, were not able to reduce ferric ions. Syringic (3,5-dimethoxy-4-hydroxybenzoic) acid did not alter the redox state of iron, only in a large excess over metal, syringic acid slightly inhibited ferrous ions autoxidation and partially reduced ferric ions. Therefore, the effects of syringic acid at high concentration were similar but much lower to those of ascorbic acid and cysteine. The biological importance of ferroxidase-like activity of polyphenols, especially the influence on iron absorption, is also discussed.     

Accelerated solvent extraction of lipids from Amaranthus spp. seeds and characterization of their composition

Standard Soxhlet extraction and accelerated solvent extraction (ASE) methods were compared for the isolation of lipids from different particle size fractions of milled amaranth seeds. Particle size was crucial for the extract yield, which was 9 times higher in case of the finest fraction (<0.23 mm) as compared with the largest particle size fraction (>0.5 mm). Soxhlet and ASE gave similar yields, however extraction rate in case of ASE was several times faster. Response surface methodology (RSM) was used to optimize the ASE parameters for maximizing extract yield from amaranth seeds. Particles size fractions (≤0.23 mm, 0.23–0.5 mm, 0.5–1 mm), extraction time (5–25 min) and temperature (40–110 °C) were selected as independent variables for a central composite design. The highest yield (13.72 g oil/100 g seeds) was obtained using the smallest particle size fraction at the temperature 90 °C and 17 min extraction time. The adequacy of the model was confirmed by extracting seed oil under optimum values given by a model. The content of triacylglycerols, squalene and fatty acid composition of oils were determined by HPLC and GC.     

Altering pasting characteristics of sweet potato starches through amino acid additives

ABSTRACT:  This study assessed the effects of amino acid additives, aspartic acid, leucine, lysine, and methionine, on the pasting and thermal characteristics of white- and orange-fleshed Beauregard sweet potato starches. A rapid visco analyzer 3D was used to determine pasting properties. In comparing pasting characteristics, starch from orange-fleshed sweet potato was found to be easier to cook, had a lower potential for retrogradation, and was less stable during heating than the white-fleshed sweet potato starch. The RVA analysis showed that the charged amino acids, aspartic acid and lysine, altered pasting characteristics of the 2 starches more than the neutral amino acids, leucine and methionine. Aspartic acid had similar effects on both starches, making them less stable during cooking and lowering the potential for retrogradation. Lysine, when added to the orange-fleshed sweet potato starch, decreased the breakdown, allowing for more stability during cooking. This study showed that pasting properties of sweet potato starches can be altered by the addition of amino acids.