Phytase–phytate–pectin hypothesis and quality of legumes cooked in calcium solutions

Hard‐to‐cook and easy‐to‐cook bean and lentil seeds were boiled in water containing calcium ions at concentrations of 0, 40, 80, 120 and 160 mg L^?1 and their texture and concentration of phytate and various peptic compounds were measured. In order to minimise matrix effects, hard‐to‐cook seeds were prepared from easy‐to‐cook seeds by soaking them at 50 °C. It was found that, as calcium ion concentration increased, phytate concentration decreased and seed hardness increased. Also, during soaking and cooking, phytate and peptic compounds were leached into the water. Losses were larger for hard‐to‐cook seeds than for easy‐to‐cook seeds. These results are consistent with the proposed theory that the formation of hard‐to‐cook legume seeds involves an interaction among divalent cations, phytate and peptic compounds, which is based on the phytase–phytate–pectin hypothesis. Copyright © 2007 Society of Chemical Industry     

Acceptability,storage stability and costing of α‐amylase‐treated maize–beans–groundnuts–bambaranuts complementary blend

The effects of α‐amylase treatment on physical properties, acceptability to mothers, and cost of roasted and extruded maize–beans–groundnuts–bambaranuts complementary porridge recipes were assessed prior to their industrial production. Storage stability of the extruded α‐amylase‐treated fortified blend was assessed at 2 weeks and 6 months by sensory evaluation, peroxide value, water activity and microbiological load. The use of α‐amylase at 0.04% w/w enhanced porridge acceptability and resulted in 88% and 122% increase in flour concentration for roasted and extrusion‐cooked porridge flour, respectively, while maintaining porridge viscosity at 1000‐fold lower than that of traditionally used porridges. The extrusion cooked blend was stable for 6 months. α‐Amylase application increased the unit cost of the developed blend by only 1.4%. The total cost was less than US $ 2 kg^?1, half the minimum price of commercially available complementary foods. Further work on marketing and the efficacy of this inexpensive food on growth of infants is warranted. Copyright © 2007 Society of Chemical Industry     

Physical,proximate, functional and pasting properties of four non‐ and γ‐irradiated bambara groundnut (Vigna subterranean) cultivars

Effect of γ‐irradiation (2–30 kGy) on physical, proximate, functional and pasting properties of four bambara groundnut cultivars was investigated. Packed (0.74–0.75 g mL^?1) and loose (0.71–0.76 g mL^?1) density varied significantly among cultivars. Generally, CIE L and hue angle decreased, while CIE a, b, deltachroma and colour intensity increased with increased dose. Protein (21.23–23.77 g/100 g), fat (6.38–7.69 g/100 g), crude fibre (1.28–3.54 g/100 g), ash (1.50–4.50 g/100 g) and moisture (10.67–12.92 g/100 g) of non‐ and γ‐irradiated bambara varied with cultivars and dose. Loose (0.41–0.49 g mL^?1) and packed (0.54–0.74 g mL^?1) densities, water absorption (1.62–2.38 g/g) and swelling (10.50–18.00 g/g) increased marginally, while oil absorption (1.93–2.82 g/g), alkaline water retention (0.66–1.23 g/g), emulsion capacity (40.31–58.23%) and stability (31.67–46.49%) decreased with increased dose. Foam capacity (6.85–22.37%) and stability (1.80–22.37%) of γ‐irradiated flours were higher than their nonirradiated (2.03–18.26%) counterparts. Nonirradiated flours showed significantly higher viscosities than their γ‐irradiated counterparts. Flours showed slightly shear‐thinning behaviours.     

Formation of protein adducts of 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine in cooked foods

Heterocyclic amines (HCAs) are mutagenic and carcinogenic compounds found in cooked meat and fish. Although HCAs are known to form adducts with protein after metabolic activation, adduct formation during cooking has not been elucidated. In this study, we showed that 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP) is released from high molecular weight compounds by acid or enzymatic hydrolysis of cooked foods. Formation of free and protein adduct forms of PhIP was dependent on cooking temperature and time, and PhIP–protein adducts were estimated to form after formation of free PhIP. We also demonstrated that PhIP–protein adduct is formed by heating of PhIP and albumin as a model protein. A new adduct peak including [M+H]⁺ (m/z=225) of PhIP as a fragment ion was detected in the high molecular weight fraction of heat‐treated protein by LC–MS analysis. From model experiments by heating of PhIP and amino acids, the adduct was estimated to be produced by condensation of the amino group of PhIP and the carboxyl group of protein. PhIP–protein adducts were detected in several cooked meat and fish at ng/g food level as PhIP content. These results suggest that food‐borne protein adducts of HCAs may influence human HCA exposure and carcinogenic risk.     

Use of soaking to enhance the bioavailability of iron and zinc from rice‐based complementary foods used in the Philippines

Complementary foods used in the Philippines are predominantly rice‐based, although enrichment with mung beans and sesame seeds is recommended despite their high content of phytic acid, a potent inhibitor of iron and zinc absorption. We have investigated the effect of soaking on the inositol penta‐ (IP5) and hexaphosphate (IP6) (analysed by HPLC), zinc, iron and calcium (via AAS) content of rice‐based complementary foods with and without the addition of mung beans and sesame seeds. Soaking rice flour for 1, 6 and 12 h at 30 °C reduced the content of IP5 + IP6 by 60, 65 and 98% respectively, with only slight changes in zinc, iron and calcium. Levels of IP5 + IP6 were reduced by 10 and 47% by soaking mung bean flour, but not whole beans, for 1 and 6 h respectively. In conclusion, soaking can be used to reduce the IP5 and IP6 content of complementary foods based on mung bean flour and/or rice flour and thus enhance the bioavailability of iron and zinc. © 2002 Society of Chemical Industry     

In vitro gas production profiles and fermentation end‐products in processed barley,maize and milo

BACKGROUND: An experiment was carried out to establish whether using a pre‐compacting device (expander) changes the contribution of dry matter (DM) and degradative behaviour of grains of barley, maize and milo pre‐processed by grinding over the different DM fractions (non‐washable (NWF), insoluble washable (ISWF) and soluble washable (SWF) fractions). Samples of the entire concentrate ingredients (WHO ingredients) and their different fractions (NWF, ISWF and SWF) were subjected to three processes (Retsch‐milled (R), expander‐treated (E) and expander‐pelleted (EP) samples) and their fermentation characteristics were evaluated using an in vitro gas production technique. RESULTS: The E process increased the size of the NWF and decreased that of the SWF compared with the R process. The ISWF of R samples was very rich in starch. The maximum fractional rate of substrate degradation and maximum rate of gas production were higher in EP samples than in R samples (P < 0.05). In maize and milo the E and EP processes shifted the pattern of fermentation towards a more glucogenic fermentation, as represented by a lower non‐glucogenic/glucogenic ratio (NGR). In all grains the ammonia concentration (NH₃‐N) and branched chain ratio (BCR) of E and EP samples were significantly (P < 0.05) lower than those of R samples. CONCLUSION: It is concluded that the E and EP processes have the potential to synchronise the fermentation of dietary proteins and carbohydrates and shift the pattern of fermentation towards a more glucogenic fermentation. Copyright © 2009 Society of Chemical Industry     

Changes in aromatic profile of fresh and dried fig – the role of pre‐treatments in drying process

The aromatic profile of volatiles in fresh figs (FF), fresh figs frozen in liquid nitrogen (NF) and dried figs (DF) (dark variety Petrova?a Crna) was characterised by HS–SPME followed by GC–MS. Figs were dried in a pilot plant cabinet dryer using different pre‐treatments to preserve the dried fruit: sulphuring and immersion in a solution of citric acid and ascorbic acid (separately). The adaptability of thin‐layer drying models to whole figs was investigated. Fresh figs and fresh figs frozen in liquid nitrogen differed mainly in the amount of aldehydes. The highest abundance of volatile compounds in dried figs was found in figs pre‐treated with sulphur dioxide and the control, compared to samples immersed in the acid solutions. Preservation was the most successful for the group of terpenes and terpenic compounds, quite good for some esters and ketones, whereas aldehydes were not affected by the used pre‐treatment.     

In vitro gas production profiles and fermentation end‐products in processed peas,lupins and faba beans

BACKGROUND: An experiment was carried out to establish whether using a pre‐compacting device (expander) changes the contribution of dry matter (DM) and degradative behaviour of peas, lupins and faba beans over the different fractions (non‐washable fraction, NWF; insoluble washable fraction, ISWF; soluble washable fraction, SWF). Samples of the entire concentrate ingredients (WHO ingredients) and their different fractions (NWF, ISWF and SWF) were subjected to three processes (Retsch milling, R; expander treatment, E; expander‐pelleting, EP) and their fermentation characteristics were evaluated using an in vitro gas production technique. RESULTS: In peas and faba beans, both the E and EP processes increased the size of the NWF (P < 0.05) and decreased the size of the SWF compared with the R process. The maximum fractional rate of gas production in the first phase of fermentation was higher in the E and EP samples than in the R samples (P < 0.05). In lupins and faba beans the E and EP processes shifted the pattern of fermentation towards a more glucogenic fermentation, as represented by a lower non‐glucogenic to glucogenic ratio (NGR). Ammonia production (NH₃‐N) in the E and EP samples was significantly (P < 0.05) lower than that in the R samples. CONCLUSION: It is concluded that the E and EP processes provide a certain level of protection against ruminal breakdown to dietary protein and shift the pattern of fermentation towards a more glucogenic fermentation. Copyright © 2008 Society of Chemical Industry     

The chelating peptide (GPAGPHGPPG) derived from Alaska pollock skin enhances calcium,zinc and iron transport in Caco‐2 cells

Gly‐Pro‐Ala‐Gly‐Pro‐His‐Gly‐Pro‐Pro‐Gly (GPAGPHGPPG), a chelating peptide derived from Alaska pollock skin, has been approved with outstanding ability to chelate calcium, zinc and iron ions. In this study, the stability of GPAGPHGPPG during in vitro gastrointestinal enzymatic digestion, the potential binding site between peptide and metal ions as well as its effects on mineral transport in Caco‐2 cells were investigated. Results showed that approximately 75% of GPAGPHGPPG remained intact at the end of the in vitro gastrointestinal enzymatic digestion. The formation of peptide‐metal complex was potentially related to histidine and cyclic structure in terms of dehydration. Moreover, GPAGPHGPPG revealed significant promotional effects on calcium (112.7%, P < 0.01), zinc (32.3%, P < 0.01) and iron (27.7%, P < 0.01) transport in Caco‐2 cell monolayer. In conclusion, GPAGPHGPPG could be developed as a potential functional ingredient to prevent mineral deficiency.     

Effect of cholesterol‐reduced and zinc fortification treatments on physicochemical,functional, textural,microstructural and sensory properties of soft cheese

The aim of this study was to produce and evaluate a soft cheese fortified with zinc and with cholesterol‐reduced content. To meet this objective, a cream base was prepared, from which cholesterol was removed using β‐cyclodextrin as extracting agent. Then, cholesterol‐reduced content cheese with and without the addition of zinc salts (ZnSO₄ or ZnCl₂) was produced. Additionally, a cheese without any treatment was prepared. Furthermore, physicochemical, textural, functional, microstructural and sensory determinations were performed. As a result, 87–94% zinc‐fortified and 93% cholesterol‐reduced cheese samples were obtained, which had similar sensorial characteristics to the cheese without treatment.     

Importance of instrumental and sensory analysis in the assessment of oxidative deterioration of omega‐3 long‐chain polyunsaturated fatty acid‐rich foods

Omega‐3 long‐chain polyunsaturated fatty acids (LC PUFA) positively influence human health. Their main dietary source is fish, especially fish oil. Owing to low fish consumption in many Western countries the average intake of omega‐3 LC PUFA is below the recommended level. This raises interest in diet supplementation and food enrichment with fish oil. However, due to a high degree of unsaturation fish oil is extremely susceptible to oxidation. Oxidation of fish oil increases when added to food products, which may be enhanced by some antioxidants, under certain conditions. For quality control of omega‐3 LC PUFA‐containing foods adequate and combined methods of oxidation assessment should be used, beginning from the raw material and continuing during processing, storage and distribution. To achieve this goal correlation of instrumental and sensory methods with multivariate data analysis may give the best results. In this paper problems of oxidation of fish oil and fish oil‐containing foods, as well as methods for its assessment, are reviewed. Copyright © 2006 Society of Chemical Industry     

The (1–3, 1–4)‐β‐Glucanases in Malting Barley: Enzyme Survival and Genetic and Environmental Effects

Eighteen barley genotypes used in Brazilian malting barley breeding programs were characterized in relation to (1–3, 1–4)‐β‐glucanase activity in green and kilned malt. They were tested to determine the loss of enzyme activity during kilning in the malting process and the environmental effects on enzyme activity were measured. The genotypes analyzed showed great variation regarding the enzyme activity in both kinds of malt, in a range from 531.94 to 934.31 U/kg in green malt, and from 187.02 to 518.40 U/kg in dry malt. The mean enzyme activity loss during kilning was close to 60%, very similar to the results obtained in other studies. The loss among genotypes varied from 8.04% to 71.54%. The enzyme activity varied significantly under the different environments tested, showing existence of environmental effects on the genotypes analyzed. Embrapa 127 was the genotype that exhibited the highest enzyme activity in finished malt although it had shown a low activity in green malt, reflecting a negligible loss of activity during kilning. The data indicate promising results to malting barley breeding due to the wide variability exhibited by genotypes as to enzyme activity and levels of isoenzyme with high thermostability.     

Production of short‐chain fatty acids following in vitro fermentation of saccharides,saccharide esters,fructo‐oligosaccharides,starches, modified starches and non‐starch polysaccharides

A range of carbohydrates including modified starches and short‐chain fatty acid esters of di‐, tri‐, tetra‐ and polysaccharides were subjected to an in vitro fermentation using human‐derived faecal bacteria. The production of the short‐chain fatty acids (SCFAs) acetate, propionate and butyrate was monitored at 6, 12, 24 and 36 h for all substrates; however, it was found that the proportions of acids produced were reasonably constant after 6 h. Between substrates there was variation in both the proportions and quantities of acids produced. Relative substrate fermentability as measured by total acid production at 24 h was: sucrose octa‐acetate > sucrose > stachyose > pregelatinised starch > Raftilose^® > verbascose > raffinose > starch acetate > bleached starch > phosphated distarch phosphate > locust bean gum > corn starch > oxidised starch = starch sodium octenyl succinate > di‐starch phosphate > acetylated di‐starch adipate = gum arabic > acid‐treated starch > gum tragacanth > gum guar > acetylated di‐starch phosphate = hydroxypropyl di‐starch phosphate > hydroxypropyl starch > pectin > raffinose undeca‐acetate > stachyose acetate > gum karaya = cellulose propionate > cellulose acetate > cellulose > cellulose butyrate > hydroxypropyl methyl cellulose > carrageenan > methyl cellulose. Chemically modified starches were similar to corn starch in the amounts of total SCFAs produced at 24 h. Synthetic sugar esters could have potential application as vehicles to deliver supraphysiological amounts of SCFAs during in vivo studies of colonic fermentation. © 2000 Society of Chemical Industry     

Fabrication of core–shell structured macrocapsules by electro‐coextrusion with agar–hydrocolloid mixtures for precooked food applications: textural and release characteristics

Textural and release characteristics of three types of core–shell macrocapsules, fabricated by electro‐coextrusion with agar only, an agar/fish gelatin (80:20) mixture or an agar/κ‐carrageenan (80:20) mixture at a total hydrocolloid concentration of 2% (w/v) and different applied voltages (0–8 kV), were investigated. The capsule diameter (1.1–1.6 mm) and shell thickness (15.1–38.4 μm) decreased with increasing applied voltage. Mixing agar with fish gelatin or κ‐carrageenan reduced slightly the capsule hardness and breaking energy; however, the capsule integrity was solid enough for safe handling. The release of core (olive oil containing a dye) in boiling water followed first‐order kinetics and was retarded significantly when κ‐carrageenan was mixed with agar but accelerated with fish gelatin addition (only 2.5–3.4 min for the release of 80% of the core). The agar/fish gelatin macrocapsules can be applied in precooked foods, because they are mechanically stable and can rapidly release the core upon contact with hot water.