Whole-grain corn tortilla prepared using an ecological nixtamalisation process and its impact on the nutritional value

Corn tortillas are produced using the traditional nixtamalisation process (TP). Nevertheless, one of the greatest problems that the tortilla industry faces is the high level of losses of solids. The aim of this research was to evaluate the nutritional value of a whole-grain tortilla, produced using an ecological process (EP). In the EP corn was cooked at 90 °C with 1.8% (w/w) calcium sulphate. The grains were steeped, washed and grounded to obtain the masa, which was baked to produce tortillas. Also, tortillas were prepared using the TP and following the same steps as those used in the EP, except that 1.0% (w/w) of calcium hydroxide was used. The tortillas from EP retained 14.05, 6.03, and 54.02% more fat, protein and fibre than tortillas produced by the TP. The PER value of rats fed whole-grain tortillas (1.81) was not different from that of rats fed the traditional tortillas (1.85).     

Prevention of the development of polluting characteristics in cooking water residue from nixtamalisation of corn by removing solid lime particles

Removing solid lime particles (SLP) may help to prevent polluting characteristics of corn cooking wastewater (nejayote). The objective of this study was to evaluate the polluting characteristics of nejayote and characteristics of nixtamal, masa and tortilla using SLP-free solutions (SLPF) for the nixtamalisation process. Two SLPF treatments: calcium hydroxide (CHYDROX) and calcium oxide (COXIDE) were compared against traditional nixtamalisation (TRADNIX). Polluting characteristics including pH, settleable solids, total hardness, alkalinity and chemical oxygen demand (COD) reduced by 29.5% and 24.3%, 61.9% and 63.3%, 46.3% and 54.7%, 43.3% and 55.1%, 41.1% and 67.7% in CHYDROX and COXIDE, respectively, compared to TRADNIX. Masas and tortillas from SLPF treatments were whiter than those from TRADNIX. Moisture in SLPF tortillas was lower by 4.3–6.3% compared to TRADNIX. Tortillas from SLPF treatments had higher maximum tensile strength (0.04–0.08 N mm⁻²) than TRADNIX. Removing SLP is a viable strategy for preventing pollution from the nixtamalisation process.     

Effect of grain tef [Eragrostis tef (Zucc.) Trotter] flour substitution with flaxseed on quality and functionality of injera

Injera from tef substituted with two flaxseed forms at 3%, 6% and 9% and control injera showed substitution had a significant effect on injera proximate, energy, titratable acidity (TA), total phenolics (TP) contents and sensory acceptability. Flaxseed forms had influence on moisture, fibre, total carbohydrate (TC) and TA. With 9% flour and whole flaxseed substitution, percentage energy, moisture, ash, crude protein, fibre and TA increase were 3.5, 27.3, 25.9, 20.4, 114.3 and 10.1, respectively. TC and pH were high for control. In all injera samples, condensed tannins and free fatty acid were insignificant. With an increase in the flaxseed substitution, most sensory acceptance increased, whereas injera eyes and colour decreased and appeared superior for control (100% tef injera). The 9% flaxseed‐substituted injera showed good proximate nutritional and energy contents of functional potential of high in dietary fibre, alpha linolenic acid, lignans, proteins and TP of anti‐oxidant nature.     

Effects of alkaline treatment on the structure of phosphorylated wheat starch and its digestibility

Phosphorylated wheat starch (PWS) was prepared with sodium trimetaphosphate and sodium tripolyphosphate (99/1, w/w), and the modified starch gave 88.8% total dietary fibre by the Prosky method and 68.7% resistant starch (RS) by the Englyst method. The stability of the phosphate esters in aqueous sodium hydroxide was investigated and related to total dietary fibre and RS contents. The phosphorylated starch was slurried (40%, w/w) at 40 °C for 4 h at pH 9.0, 10.0, 11.0, and 12.0. The phosphorus content of the PWS decreased from 0.37% to 0.29% after treatment at pH 12.0, whereas only a slight decrease in phosphorus content occurred after treatments at pH 9.0–11.0. Despite the 22% decrease in total phosphorus content, total dietary fibre content and RS content of the alkali-treated PWS changed only slightly. ³¹P nuclear magnetic resonance spectroscopy showed that after the alkali treatment at pH 12.0, cyclic monostarch monophosphate and monostarch diphosphate were not detectable and that the level of total monostarch monophosphate decreased from 0.077% to 0.067%. Conversely, distarch monophosphate increased from 0.17% to 0.20%, of ≈18%. The increase in distarch monophosphate (cross-linking) content after alkali treatment at pH 12.0 probably explained the retention of total dietary fibre and RS contents in the alkali-treated PWS.     

Nutraceutical Properties of Flour and Tortillas Made with an Ecological Nixtamalization Process

The traditional nixtamalization (TN) process, used for obtaining maize‐based products, negatively affects bioactive compounds because of its highly alkaline pH. Recently, an ecological nixtamalization (EN) process has been developed that retains the pericarp and maintains the nejayote (wastewater) within the acidic‐neutral range. This study examines the effect of pH on the nutraceutical compounds (NC) of maize, such as polyphenolics and anthocyanins (ANT), as well as the effect on the antioxidant capacity (AC). The highest concentration of total phenolics (TP) in the maize kernel was found in the black and yellow genotypes, the highest concentration of ANT in the black genotypes, and the highest concentration of AC in the red and white genotypes. In the flour, TP levels were between 206 to 400 mg GA/100 g, ANT levels were 141 to 4107 mg cyanidin‐3 glucoside/kg, and AC levels were 2544 to 3001 mg AA/kg. In tortillas, TP levels were 255 to 319 mg GA/100 g, ANT levels were 32 to 3420 mg cyanidin‐3 glucoside/kg, and AC levels were from 1513 to 2695 mg AA/kg. The reduced loss of soluble solids, the pH, and the formation of compounds with proteins and carbohydrates from the EN process positively affected NC retention.     

Enhancement of Corn Nixtamalization by Power Ultrasound

Nixtamalization, a key production step for masa flour used for tacos, corn tortillas, and chips, traditionally involves corn kernel cooking for 1 h and a lengthy process of steeping (16–18 h) in a lime solution. This study aimed at accelerating the traditional nixtamalization (TN) process using power ultrasound with acoustic energy density around 1.85 W/g for 1 h during cooking followed by brief steeping for 1 h. The cooked kernels (nixtamal) were evaluated for texture and color, while the cooking liquor (nejayote) was evaluated for solid losses. The power ultrasound-assisted nixtamalization resulted in significantly (p?≤?0.05) reduced process time and softer nixtamal with less solid losses in nejayote than control (TN). Response surface methodology established significant relationships of sonication duration and cooking temperature to texture, color of nixtamal, and dry matter loss in nejayote. This study indicates that power ultrasound ameliorated traditional nixtamalization in terms of quality and operation time.     

Production of a potential collagenolytic protease by nejayote fermentation with Aspergillus oryzae

Nejayote is the wastewater obtained from maize lime cooking. It was used for Aspergillus oryzae growth and enzyme production. Protein production and collagenolytic activity were evaluated to test the effects of pH, spore inoculum and nejayote content in a 3³ factorial design. No collagenolytic activity was observed in the supernatant of the fermentation without nejayote. Using nejayote at 5% increased 1.5 times the fungus growth in comparison with nejayote 1% and 3%; and the maximum collagenolytic activity was reached after 3 days at pH 8 (P < 0.05). After sequencing, a 32 kDa alkaline protease was identified. Along with the alkaline conditions produced by the inclusion of nejayote solids, this waste is an important source of carbohydrates that improved the growth of A. oryzae to produce a protease that has the potential to break collagen. This permits a prospective revalorisation of a waste material to get a product with multiple biotechnological uses.     

Phosphorus concentration and solubility in dairy feces: variability and affecting factors

Recent data from phosphorus (P) feeding trials have demonstrated that P concentration in dairy feces is directly affected by P levels in diets and that farm P surpluses as well as potential environmental losses can be reduced through dietary manipulation. The current study was conducted to examine the variability of fecal P under farm conditions and to elucidate factors affecting the concentration and solubility of fecal P. Feed and fecal samples from >30 commercial dairies in the Northeast and Mid-Atlantic regions were analyzed. Dietary P concentrations ranged from 3.45 to 5.78 g/kg of feed DM (DM), and P determined in acid digests (TP) of feces from 5.84 to 12.84 g/kg of fecal DM. On average, 50% of fecal TP was water soluble; of the latter, 83% was inorganic (Pi). Across-farm variability (n=33) had CV averaging 18.9% for fecal TP and >20% for Pi and total P (Pt) in water extracts. Within-farm variability based on multiple samples per herd had the same magnitude as across-farm and was independent of sample numbers from individual farms (n=7 to 30). Of all fecal parameters determined, pH and DM had the lowest variability (CV <10%), water-soluble Pi, Pt, and Ca the highest (CV of 20 to 30%), and total P, Ca, and Mg determined by acid digests were intermediate (CV 10 to 20%). Water-soluble Pi concentrations determined in dried-ground fecal samples were lower than in wet samples. The drying-grinding process changes Pi solubility and the change is not linear. This study confirms that dietary P concentration is the dominating factor affecting fecal P excretion; however, Ca concentration, DIM, and fecal pH also made small, but statistically significant contributions, although some of the mechanisms remain to be thoroughly investigated.     

Characterisation of low-fat high-dietary fibre frankfurters

Two different peach dietary fibre (DF) suspensions (17 and 29%) were used to obtain low-fat high-DF frankfurters (20-5% fat) which were compared to an all-meat control (25% fat). The viscosity of the meat batters increased with DF content. The protein (11.5±0.6%) and collagen (1.4±0.1%) contents of frankfurters were not affected by DF addition, and the higher the DF content, the lower the pH (6.4 to 5.8) due to the fibre solution acidity. The DF was effective in retaining added water in low-fat frankfurters since their cooking losses were similar to those of the controls (5.5±0.1%). Low-fat frankfurters were darker and browner than the controls and only high fibre addition significantly decreased the textural parameters. Sensory evaluation indicated that low fat-high DF frankfurters (20, 15 and 10% fat) were as acceptable as the all-meat frankfurters.     

酶法提取麒麟菜膳食纤维工艺的研究

分别采用正交和均匀设计法,优选出麒麟菜(Eucheuma)膳食纤维的最佳漂白和提取工艺条件,并对提取的膳食纤维进行了分析。结果表明:最佳漂白条件--漂白液浓度2g/L、pH7.0、漂白时间40min;最佳提取条件--加水量4%(L/g)、煮沸时间60min、在60～65℃下分别加入0.15%的蛋白酶和0.1%的α-淀粉酶、分别酶解60和30min。在此条件下,提取率为39.06%,膨胀力为38.6ml/g、持水力为2045.8%,膳食纤维含有较低的蛋白质、脂肪且无淀粉检出,具有较高含量的Ca、P、K等矿物元素,其功能指标优于化学法提取的麒麟菜膳食纤维和小麦麸皮标准膳食纤维,有望在人体中发挥重要的生理功效。     

Effect of natural and controlled fermentation on flatus‐producing compounds of beans (Phaseolus vulgaris)

Fermentation of grain legumes is an efficient method to reduce the concentration of α‐galactosidic compounds that are known to be flatulence producers. Soluble dietary fibre has also been implicated in flatulence production; however, little information exists about the effectiveness of fermentation in diminishing the effects of these compounds. The objective of this work was to study the effect of natural fermentation (NF) and controlled fermentation (CF) on the content of α‐galactosides and dietary fibre in dry beans (Phaseolus vulgaris) for 24, 48, 72 and 96 h. After 48 h, the pH during NF dropped from 6.15 to 4.00 and the nominal acidity increased six times; for CF, however, although the decrease in pH was similar to that for NF, the nominal acidity increased only three times after 48 h. Insoluble fibre content did not change the pH significantly after 96 h for NF and CF. Soluble fibre suffered an apparent removal after 48 h of NF and underwent a sharp reduction of 66% after 96 h of CF. The concentration of stachyose (the main α‐galactoside in raw beans) diminished notably after 48 h and 96 h NF (72% and 95% respectively), whereas with CF only 11% was removed after 96 h. NF of P vulgaris seems to be more effective than CF in reducing the flatulence‐producer factors (α‐galactosides and soluble dietary fibre). Copyright © 2003 Society of Chemical Industry     

Enhancement with varying phosphate types, concentrations, and pump rates, without sodium chloride on beef biceps femoris quality and sensory characteristics

Beef biceps femoris muscles (n=45) were used to evaluate the effect of enhancement with solutions containing sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), or tetrasodium pyrophosphate (TSPP) at either 0.2% or 0.4% of product weight, without sodium chloride. All solutions were injected into muscle samples at either 112% (12% pump) or 118% (18% pump) of raw product weight. Muscles enhanced with STPP or TSPP had a higher (P<0.05) pH than SHMP or untreated muscles (CNT), whereas there was no difference (P>0.05) in pH between SHMP and CNT. Muscles enhanced with STPP had less (P<0.05) free water than CNT, whereas SHMP and TSPP did not differ from CNT. However, direct comparison of phosphate types revealed no difference (P>0.05) in free water. Steaks enhanced with SHMP had greater (P<0.05) cooking losses than CNT, whereas steaks treated with STPP or TSPP did not differ (P>0.05) from CNT. Phosphate inclusion at 0.2% allowed for greater (P<0.05) cooking losses than CNT, whereas 0.4% phosphate inclusion exhibited similar (P>0.05) cooking losses as CNT. Although there were no differences (P>0.05) in cooking loss between pump rates, steaks enhanced at an 18% pump rate had greater (P<0.05) cooking losses than CNT, whereas those enhanced at 12% had similar (P>0.05) cooking losses as CNT. Enhancement with any of the three phosphate types or either concentration did not improve (P>0.05) sensory tenderness or juiciness characteristics compared to CNT, but enhancement at an 18% pump rate allowed for improved (P<0.05) overall tenderness, compared to a 12% pump rate. These results suggest that while phosphate enhancement independent of sodium chloride generally did not improve water retention, cooked yields and palatability compared to untreated samples, utilizing higher phosphate concentrations or utilizing STPP or TSPP effectively retained the additional water associated with solution enhancement, allowing for similar free water and cook yields as untreated samples.     

By-products from different citrus processes as a source of customized functional fibres

Dietary fibre encompasses a huge variety of macromolecules, exhibiting a wide range of physicochemical properties. Citrus fibre can be obtained from different industrial sources and different kinds of citrus. The chemical components of fibre (pectin, lignin, cellulose and hemicellulose), together with other compounds, such as flavonoids, were analysed in nine different industrial sources. Final fibre composition was more dependent on the industrial process than on the type of citrus. The chemical changes gone by citrus fibre showed losses of functional values; i.e. soluble dietary fibre and ascorbic acid content decreased when waste products were transformed into fibres. The water-holding and lipid-holding capacities of analysed citrus fibres suggested a non-linear behaviour of these properties for the analysed citrus fibres.     

Microencapsulation of Corn Wastewater (Nejayote) Phytochemicals by Spray Drying and Their Release Under Simulated Gastrointestinal Digestion

Corn lime cooking generates a large amount of wastewater known as nejayote that is composed of suspended solids and solubilized phytochemicals. Spray drying can be an alternative to recover bioactive molecules, such as ferulic acid, from nejayote. Besides the yield, the physicochemical properties (solubility, water activity, pH, moisture, hygroscopicity, total phenolic content, and distribution of free and bound hydroxycinnamic acids) of spray‐dried nejayote powders were analyzed. The powders were obtained at 200 °C/100 °C or 150 °C/75 °C (inlet/outlet) air temperatures with the addition of maltodextrin (MD) or 2‐hydroxypropyl‐beta‐cyclodextrin (HBCD) as encapsulating agents. Even when no carrier agent was used, a spray‐dried nejayote powder was produced. The use of MD or HBCD as carrier increased the yield from 60.26% to 68.09% or 71.83%, respectively. As expected, a high inlet temperature (200 °C) allowed a satisfactory yield (>70%) and a low powder moisture (2.5%) desired by the industry. Water activity was reduced from 0.586 to 0.307 when HBCD was used in combination with a drying inlet temperature of 150 °C; and from 0.488 to 0.280 when the inlet temperature was set at 200 °C. Around 100% bioaccessibility of the compounds was observed after in vitro digestion. The addition of HBCD increased the release time (P < 0.05). Under simulated physiological conditions, there was no reduction of total phenolics, suggesting a good stability. This paper showed the feasibility to engage the spray drying technology to the corn industry to minimize their residues and reuse their by‐products.     

In vitro availability of calcium from sources of cellulose,methylcellulose, and psyllium

Certain types of dietary fibres may decrease the amount of dietary calcium available for absorption. The objective of this study was to determine the in vitro calcium availability from sources of cellulose, methylcellulose, and psyllium, such as cereals, fibre supplements, and purified fibres. Total dietary fibre, soluble and insoluble dietary fibre, acid detergent fibre, neutral detergent fibre, cellulose, hemicellulose, lignin, protein, uronic acid, phytate, water holding capacity, and total endogenous calcium content were determined. Results from the chemical analyses of the fibre sources varied significantly. Free endogenous calcium, at pH 3–8, was determined via gel filtration. Calcium was added to each fibre source and free exogenous calcium was determined via gel filtration at pH 1 and pH 8. The analysis of variance procedure was used to determine differences in binding capacities of the fibres. There was virtually no binding of exogenous calcium by sources of cellulose, methylcellulose, or psyllium.     

Effect of insoluble dietary fibre addition on technological,sensory, and structural properties of durum wheat spaghetti

Insoluble fibres are important in human health and disease prevention and can be incorporated into food. High fibre pasta prepared with bran is typically inferior quality compared to durum pasta. This study compared spaghetti prepared from durum semolina substituted with various amounts of either durum bran or germ (pollard) dried at high temperature. Pasta was evaluated for cooking properties, texture, sensory, fibre content, antioxidant status (AO) and in vitro starch digestibility to determine the dose producing acceptable quality. Pollard at 10% substitution had minimal impact on quality with higher AO and fibre. Above 30%, pasta had undesirable colour, sensory properties and higher starch digestion. Although bran substituted pasta had undesirable sensory and technological properties, especially at 30% incorporation, it does provide more dietary fibre and antioxidants than regular pasta and does not affect starch digestibility. Interestingly, a significant amount of AO was retained in the cooked pasta. The study illustrates the value of structural analysis to explain observed technological properties of the product with fibre inclusion.     

Physicochemical Properties of Dietary Fibres Prepared from Ambarella (Spondias cytherea) and Mango (Mangifera indica) Peels

The preparation of fibres from mango and ambarella peels can offer a way to upgrade by-products. Comparatively to lime, ambarella and mango fibres were prepared from their corresponding peels using ethanolic treatment (85% at 70 °C/5 min). The peels were characterised for their dry matter content, pH and apparent viscosity. The soluble dietary fibre (SDF) and insoluble dietary fibre (IDF) contents of the samples were determined. Hydration capacity of these fibres was evaluated. Results showed that the ethanolic treatment of the peels (85% at 70 °C/5 min) had significant (p?<?0.05) effects on the contents of neutral sugars and uronic acid (from 105 to even 203 mg/g in case of mango fibre). For ambarella fibres, the proportion of IDF (51%) was highest and that of SDF (34%) was lowest. Mango and lime fibres exhibited similar values of IDF (40–43%) and SDF (50–57%). Mango peel fibres had higher hydration capacities than ambarella and lime fibres. The best dietary fibres content and the high hydration capacities of mango peel fibres favour their exploitation in dietary fibre-rich foods preparation.     

Effect of dietary protein concentration on ammonia and greenhouse gas emitting potential of dairy manure

Two experiments were conducted to investigate the effect of dietary crude protein concentration on ammonia (NH(3)) and greenhouse gas (GHG; nitrous oxide, methane, and carbon dioxide) emissions from fresh dairy cow manure incubated in a controlled environment (experiment 1) and from manure-amended soil (experiment 2). Manure was prepared from feces and urine collected from lactating Holstein cows fed diets with 16.7% (DM basis; HCP) or 14.8% CP (LCP). High-CP manure had higher N content and proportion of NH(3)- and urea-N in total manure N than LCP manure (DM basis: 4.4 vs. 2.8% and 51.4 vs. 30.5%, respectively). In experiment 1, NH(3) emitting potential (EP) was greater for HCP compared with LCP manure (9.20 vs. 4.88 mg/m(2) per min, respectively). The 122-h cumulative NH(3) emission tended to be decreased 47% (P=0.09) using LCP compared with HCP manure. The EP and cumulative emissions of GHG were not different between HCP and LCP manure. In experiment 2, urine and feces from cows fed LCP or HCP diets were mixed and immediately applied to lysimeters (61×61×61 cm; Hagerstown silt loam; fine, mixed, mesic Typic Hapludalf) at 277 kg of N/ha application rate. The average NH(3) EP (1.53 vs. 1.03 mg/m(2) per min, respectively) and the area under the EP curve were greater for lysimeters amended with HCP than with LCP manure. The largest difference in the NH(3) EP occurred approximately 24 h after manure application (approximately 3.5 times greater for HCP than LCP manure). The 100-h cumulative NH(3) emission was 98% greater for HCP compared with LCP manure (7,415 vs. 3,745 mg/m(2), respectively). The EP of methane was increased and that of carbon dioxide tended to be increased by LCP compared with HCP manure. The cumulative methane emission was not different between treatments, whereas the cumulative carbon dioxide emission was increased with manure from the LCP diet. Nitrous oxide emissions were low in this experiment and did not differ between treatments. In the conditions of these experiments, fresh manure from dairy cows fed a LCP diet had substantially lower NH(3) EP, compared with manure from cows fed a HCP diet. The LCP manure increased soil methane EP due to a larger mass of manure added to meet plant N requirements compared with HCP manure. These results represent effects of dietary protein on NH(3) and GHG EP of manure in controlled laboratory conditions and do not account for environmental factors affecting gaseous emissions from manure on the farm.     

Physicochemical,antioxidant properties and in vitro digestibility of wheat–purple rice flour mixtures

The physicochemical characteristics, antioxidant properties and in vitro digestibility of high‐antioxidant content flours made from different combinations of Thai purple rice flour and refined wheat flour from 25%, 50% to 75% (w/w) were investigated and these were compared with whole flour from purple rice and refined wheat flour. The increase in substitution levels of purple rice flour affected all the functional properties of flours, at the same time the levels of dietary fibre, protein digestibility and antioxidant compositions were also changed. The purple rice flour exerted a particularly strong effect on starch digestibility as the purple rice increased to 50% in the mixture. Moreover, purple rice flour showed lower amounts of rapidly digested starch (RDS), whereas slowly digested starch (SDS) of whole flour from purple rice and 75% substitution purple rice flour was found to be the highest for all samples. The in vitro starch digestibility of all samples also showed a positive correlation between dietary fibre and antioxidant compounds. Overall, the addition of purple rice flour improved the final nutritional properties, notably a lower predicted glycaemic index, and a higher antioxidant potential, which are two important nutritional properties for human health.     

Utilization of cereal and fruit fibres in low fat dry fermented sausages

The effect of addition of cereal and fruit dietary fibres on the sensory properties of reduced-fat, dry fermented sausages was studied. Dry fermented sausages with 6 and 10% pork backfat were manufactured, with addition of cereal (wheat and oat) and fruit (peach, apple and orange) dietary fibres, at 1.5 and 3% concentrations. The energy value reduction of the final products was close to 35% and their final fibre contents, after ripening, were 2 and 4%, respectively. The ripening process was monitored by physico-chemical and microbiological analysis. Sensory properties were analyzed using triangular and hedonic tests and, a texture profile analysis was carried out. A correlation principal component analysis was performed. The results showed that the sensory and textural properties of batches with 3% dietary fibre were the worst, due to their hardness and cohesiveness. The best results were obtained with sausages containing 10% pork backfat and 1.5% fruit fibre especially those with orange fibre, which gave organoleptic characteristics similar to conventional high fat products. Thus, reduced fat sausages fortified with dietary fibre can be obtained with an acceptable sensory profile.