Phytic acid and its interactions: Contributions to protein functionality,food processing,and safety

Is phytic acid (IP6) an undesirable constituent for vegetables and foods? This question is getting harder to answer. Phytic acid contributes to mineral/protein deficiency, but also brings about potential physiological benefits. Both the positive and negative effects boil down to the interactions among IP6, metal ions, and biopolymers. In the wake of the booming market of plant-based foods, an unbiased understanding of these interactions and their impacts on the foods themselves is a necessity to the smart control and utilization of plant-sourced phytates. This overview presents updated knowledge of IP6-related interactions, with a strong focus on their contributions to food functionality, processability, and safety.     

Phytic acid level in infant flours

This study determined the phytic acid content in the infant flour commonly consumed in the Canary Islands. A total of 400 samples from different cereals was analyzed. The method proposed by Garcı́a-Villanova et al. (1982) [Garcı́a-Villanova, R., Garcı́a-Villanova, R. J., Ruiz de Lope, C. (1982). Determination of phytic acid by complexometric titration of excess of iron (III). Analyst 107, 1503–1506] was the one used for determination of the phytic acid content in cereal flours. Phytic acid concentrations are within the range <1–⩾36 mg/g. The arithmetic mean obtained from all the samples studied is 24.6 mg/g. Most of the samples studied show a phytic acid content higher than 20 mg/g, and much lower values are observed in gluten-free flours (< 5 mg/g). Significant differences are observed for the different flour types. Gluten-free flour has a content lower than the rest; 9-cereal flour has a phytate concentration lower than the other flours tested but higher than gluten-free flour. Among wheat samples, phytate values are lower than in the varieties muesli-chocolate, 7-cereal, 8-cereal, multicereal and cereal-biscuit. Multicereal flour has a lower content than muesli-chocolate.     

Phytic acid in health and disease

Phytic acid (PA), a major phosphorus storage compound of most seeds and cereal grains, contributes about 1 to 7% of their dry weight. It may account for more than 70% of the total kernel phosphorus. PA has the strong ability to chelate multivalent metal ions, especially zinc, calcium, and iron. The binding can result in very insoluble salts that are poorly absorbed from the gastrointestinal tract, which results in poor bioavailability (BV) of minerals. Alternatively, the ability of PA to chelate minerals has been reported to have some protective effects, such as decreasing iron‐mediated colon cancer risk and lowering serum cholesterol and triglycerides in experimental animals. Data from human studies are still lacking. PA is also considered to be a natural antioxidant and is suggested to have potential functions of reducing lipid peroxidation and as a preservative in foods. Finally, certain inositol phosphates, which may be derived from PA, have been noted to have a function in second messenger transduction systems. The potential nutritional significance of PA is discussed in this review.     

Degradation of sorbic acid in model food systems

Solutions of sorbic acid are unstable in the presence of sulphur dioxide and light. At pH 2·1 in the presence of excess sulphur dioxide, sorbic acid was totally degraded in 8 days. Sorbic acid was also unstable in solutions of dilute sulphuric acid. Two volatile products from the degradation in sulphur dioxide solution and in dilute sulphuric acid were identified as α-angelica lactone and 2-methyl-5-acetylfuran.     

植酸的食品保鲜机理及应用

通过植酸的分子结构,分析了植酸的理化特性及高效螯合金属离子的作用机理。介绍了植酸在食品行业中作为抗氧化剂、护色剂、沉淀剂的理论研究和应用概况,并对植酸食品保鲜技术进行了展望。     

Phytic acid content in milled cereal products and breads

Phytic acid was determined in cereal (brans, flours and milled wheat-products) and breads. The method was based on complexometric titration of residual iron (III) after phytic acid precipitation. The cereal flours showed values ranged between 3–4 mg/g for soft wheats, 9 mg/g for hard wheat and 22 mg/g for whole wheat. Corn, millet and sorghum flours reported a mean of 10 mg/g and oat, rice, rye and barley between 4 and 7 mg/g. Wheat brans had wide ranges (25–58 mg/g). The phytic acid for oat brans was half that of wheat bran (20 mg/g) and higher value (58 mg/g) than that for rice bran. The milling products (semolinas) from hard wheat exhibited 10 mg/g and soft wheat a mean of 23 mg/g. The breads made with single or mixture cereal flours exhibited ranges between 1.5 and 7.5 mg/g. The loss of phytic acid relative to unprocessed flours was between 20% for oat bread and 50% for white bread.     

A food systems approach to researching food security and its interactions with global environmental change

There is growing concern that satisfying societal demand for food over coming decades will be increasingly challenging. Much of the debate centres on increasing food production which has always been–and remains–an important strategy to alleviate food insecurity. However, despite the fact that more than enough food is currently produced per capita to adequately feed the global population, about 925 million people remained food insecure in 2010. Meeting future demand will be further complicated by deleterious changes in climate and other environmental factors (collectively termed ‘global environmental change’, GEC). This paper lays out a case for a food systems approach to research the complex food security/GEC arena and provides a number of examples of how this can help. These include (i) providing a framework for structuring dialogues aimed at enhancing food security and identifying the range of actors and other interested parties who should be involved; (ii) integrating analyses of the full set of food system activities (i.e. producing, storing, processing, packaging, trading and consuming food) with those of the food security outcomes i.e. stability of food access, utilisation and availability, and all their nine elements (rather than only food production); (iii) helping to both assess the impacts of GEC on food systems and identify feedbacks to the earth system from food system activities; (iv) helping to identify intervention points for enhancing food security and analysing synergies and trade-offs between food security, ecosystem services and social welfare outcomes of different adaptation pathways; and (v) highlighting where new research is needed.     

Relative importance and interactions of furan precursors in sterilised,vegetable-based food systems

Mitigation strategies aimed at an intervention in the reaction pathways for furan formation (e.g., by adjusting precursor concentrations) might offer an additional route for furan reduction in sterilised, vegetable-based foods, without adverse effects on other food safety or quality attributes. As a first step towards product reformulation, the aim of the present study was to determine the relative importance and interactions of possible furan precursors in these types of foods. Based on an I-optimal experimental design, potato purée (naturally low in furan precursors) was spiked with known amounts of sugars, ascorbic acid, olive oil and β-carotene, and subjected to a thermal sterilisation. Significant correlations were observed between furan concentrations after thermal treatment and starting concentrations of ascorbic acid and monosaccharides (i.e., fructose and glucose). Ascorbic acid had a clear furan-reducing effect as an antioxidant by protecting (polyunsaturated) fatty acids against oxidative degradation. Fructose and glucose were the main precursors, which can most probably be attributed to their high, but realistic, concentrations in the product. The contributions of fatty acids and β-carotene were strongly dependent on redox interactions with other food constituents. In the same potato purées, only low concentrations (0–2 ng g^–1 purée) of 2-methylfuran were detected, indicating that the direct importance of the spiked food constituents as a precursor for methylfuran formation was rather small. Based on the results of this study, reducing the amount of monosaccharides or adjusting the redox conditions of the matrix are suggested as two possible approaches for furan mitigation on the product side.     

Liposomal stabilization of ascorbic acid in model systems and in food matrices

Ascorbic acid (AA) was encapsulated into dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylcholine/cholesterol (DPPC/chol) liposomes. We have shown that co-encapsulation of citric and ascorbic acids into liposomes results in considerable stabilization of the latter in model systems containing catalytic concentrations of copper ions. The rate of AA oxidation was decreased by up to 300-fold that of free AA. Incorporation of cholesterol into membranes resulted in lower stabilization efficacy at room temperature and better thermal stability at higher temperatures than pure DPPC liposomes. Total AA, extra-liposomal AA and leakage of AA out of liposomes during thermal treatment were evaluated using the free radical 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS). A modification of the ABTS based assay for liposome permeability makes it applicable to reducing agents and antioxidants as well as AA. Encapsulated AA was also stabilized in real food matrices. The rate of AA oxidation in apple juice, relative to that of free AA, was decreased by two orders of magnitude when encapsulated in DPPC liposomes and by more than one order of magnitude in DPPC/chol liposomes. Liposomal stabilization of AA in a fermented milk product was less pronounced.     

Phytic acid in sunflower seeds,pressed cake and protein concentrate

High levels of phosphorus (P) and zinc (Zn) were observed in sunflower seeds. Most of the phosphorus is present in the form of phytic acid. The contents of phytic acid in sunflower seeds, pressed cake and protein concentrate were found to be 1·6%, 4·3% and 3·1%, respectively.     

Phytic acid in Indian soybean: genotypic variability and influence of growing location

Phytic acid, the heat‐stable anti‐nutritional factor, was determined in 80 cultivars/strains of Indian soybean to identify genotypes that possess low concentrations of phytic acid. Variation of values of 28.6–46.4 g kg⁻¹ soy flour was observed. Information on the influence of growing locations with widely differing soil types on phytic acid content being scarce, phytic acid in the mature dry seeds of eight Indian soybean cultivars grown over four locations was evaluated. Variation in different varieties at different locations was 27.8–45.0 g kg⁻¹ soy flour. Averaged over eight genotypes, the maximum mean value for phytic acid was observed at Pantnagar and the minimum at Palampur. These differences in locational mean values for phytic acid can be explained on the basis of characteristics of the soils and environment. The higher mean value at Pantnagar may be attributed to higher soil organic phosphorus, nearly neutral pH and favorable temperature from flowering to maturity. However, the lower value observed at Palampur can be explained by the acidic nature of its soil, with lower maximum and minimum temperatures prevailing from flowering to maturity. Locational and genotypic × locational effects were found to be significant (p < 0.01). The results indicated that soil characteristics and soil environment play a significant role in the accumulation of phytic acid in soybean seeds. Copyright © 2005 Society of Chemical Industry     

Role of sorbic acid in nonenzymic browning reactions in liquid and solid model food systems

Role of sorbic acid (SA) in browning development in model systems has been studied. In liquid model systems containing water-glycerol-glucose (WGG), water-glycerol-sucrose (WGS), 45% sucrose and 30% sucrose plus 15% glucose, SA degraded when stored at 37°C forming brown pigments. Addition of amino acids (glycine or lysine monohydrochloride) increased the rate of browning development while Cu²⁺ reduced SA degradation and browning development. In the absence of amino acids and SA, WGG and WGS systems did not brown appreciably.
In solid systems with SA adsorbed on microcrystalline cellulose, the maximum rate of browning occurred at 0.73 a_w , but maximum rate of SA loss was at 1.0 a_w . In all systems inclusion of amino acids reduced SA degradation but increased browning development. The rate of SA-induced browning was considerably higher than that caused by sugar-amino acid interactions.     

碘量法检测植酸含量方法的校正

本文采用标准植酸钠对硫酸铜－碘量法测定植酸含量的计算公式进行了校正。原方法算得标样的五氧化二磷含量超过实际值的１１．６７％，校正后的换算系数民理论换算系数相差只有１．３８％，说明理论换算系数是可信的。     

Phytic acid and extractable phosphorus of pearl millet flour as affected by natural lactic acid fermentation

Lactic acid fermentation of pearl millet flour decreased its phytic acid content and increased extractable phosphorus. Fermentation at 40 and 50°C for 72 h or longer eliminated phytic acid almost completely; extractable phosphorus was more than doubled. Lower temperatures (20 and 30°C) were less effective. The changes in concentration of phytic acid and extractable phosphorus may be attributed partly to phytase activity inherent in pearl millet flour.     

食品中水杨酸的测定

通过采用高效液相色谱分析技术,测定碳酸饮料、果酱、红枣核桃粉中水杨酸成分含量,建立高效液相色谱测定食品中水杨酸含量.采用水浴加热法去除样品中乙醇及二氧化碳等干扰成分,并用高效液相色谱法,Phenomenex luna 5μmC18色谱柱(250×4.60mm);流动相为乙酸胺(0.02mol/L):甲醇:冰醋酸(91 : 9 : 0.15)系统;流速为1.0mL/min;进样量为10μL;检测波长为:230nm,0.2AUFS,紫外检测器.采用外标法定量测定食品中水杨酸的含量.对不同样品进行水杨酸含量测定时,其加标回收率均在:87%97%.本法简便快速、灵敏度和精密度高、准确可靠,可适用于食品中水杨酸含量的日常测定.     

Phytic Acid Determination in Soybeans

Several established methods of phytic acid determination in soybeans were evaluated. Iron analysis methods, which rely on a 4:6 molar ratio of Fe:P, were eliminated because this ratio was not dependable. Three assay methods relying on phosphorus analysis were then compared. The anion-exchange method was considered most accurate but not convenient for routine analysis. Analysis of the ferric phytate precipitate and a new method, analysis of the supernatant before and after ferric chloride precipitation, were judged against the anion-exchange method under different extraction conditions. Based upon good agreement with anion-exchange column results and acceptable reproducibility, the best methods were (1) precipitate analysis of phosphorus after extraction with 3% TCA + 10% sodium sulfate, or (2) the supernatant difference method after extraction with 1.2% HCl.     

Information systems in food safety management

Information systems are concerned with data capture, storage, analysis and retrieval. In the context of food safety management they are vital to assist decision making in a short time frame, potentially allowing decisions to be made and practices to be actioned in real time. Databases with information on microorganisms pertinent to the identification of foodborne pathogens, response of microbial populations to the environment and characteristics of foods and processing conditions are the cornerstone of food safety management systems. Such databases find application in: Identifying pathogens in food at the genus or species level using applied systematics in automated ways. Identifying pathogens below the species level by molecular subtyping, an approach successfully applied in epidemiological investigations of foodborne disease and the basis for national surveillance programs. Predictive modelling software, such as the Pathogen Modeling Program and Growth Predictor (that took over the main functions of Food Micromodel) the raw data of which were combined as the genesis of an international web based searchable database (ComBase). Expert systems combining databases on microbial characteristics, food composition and processing information with the resulting "pattern match" indicating problems that may arise from changes in product formulation or processing conditions. Computer software packages to aid the practical application of HACCP and risk assessment and decision trees to bring logical sequences to establishing and modifying food safety management practices.In addition there are many other uses of information systems that benefit food safety more globally, including: Rapid dissemination of information on foodborne disease outbreaks via websites or list servers carrying commentary from many sources, including the press and interest groups, on the reasons for and consequences of foodborne disease incidents. Active surveillance networks allowing rapid dissemination of molecular subtyping information between public health agencies to detect foodborne outbreaks and limit the spread of human disease. Traceability of individual animals or crops from (or before) conception or germination to the consumer as an integral part of food supply chain management. Provision of high quality, online educational packages to food industry personnel otherwise precluded from access to such courses.