Nutritional and functional characterisation of hydrolysates from quinoa flour (Chenopodium quinoa) using two proteases

The objective was to study the nutritional and functional properties of hydrolysates from quinoa (Chenopodium quinoa) obtained by enzymatic hydrolysis of defatted quinoa flour (DQF). The commercial enzymes alcalase and flavourzyme were used to obtain the hydrolysates defatted quinoa flour hydrolysate with alcalase (DQFA) and defatted quinoa flour hydrolysate with flavourzyme (DQFF), respectively, after 3 h of digestion at 50°C and pH 8. The degree of hydrolysis (47.32%), yield (31.05%) and protein recovery (88.80%) values were higher in DQFA; however, its protein content (48.34%) was lower compared to that of DQFF (55.06%). Also, DQFA had a solubility greater than 57% over a wide pH range (2–10) and good foam stability (70–90%). On the other hand, DQFF presented adequate emulsifying activity (61.30 m²/g), emulsifying stability (158.62 min) and foaming capacity (131%). Due to the high content of macro- and micronutrients and adequate emulsifying and foaming properties, DQFA and DQFF could be used as ingredients in various processed food products and protein supplements.     

Effects of microwave heating,steaming, boiling and baking on the structure and functional properties of quinoa (Chenopodium quinoa Willd.) protein isolates

The effects of microwave heating (MW), steaming (SM), boiling (BL) and baking (BK) on the structure and functional properties of quinoa protein isolates (QPI) were investigated. SDS-PAGE showed the 20–30 kDa band strength of QPI-BL was enhanced, which indicated the disulphide bond was broken and protein molecules dissociated. Due to the recombination of subunits, some large molecular weight or insoluble polymer components of QPI-SM and QPI-BK did not pass through the gel. Microwave heating and boiling showed negative effects for α-helix and positive effects for β-sheet, which implied the molecular structure was transformed from ordered to disordered, the secondary structure became loose. The reduction of free SH (sulfhydryl) and surface hydrophobicity implied that aggregation and cross-linking of protein molecules for QPI-SM and QPI-BK. QPI, QPI-MW and QPI-BL exhibited better solubility, which was related to the water holding capacity (WHC) and emulsification. For QPI-SM and QPI-BK, functional properties (including solubility, WHC and gel-forming ability) decreased due to molecular aggregation. Heat treatments significantly affect the structure and functional properties of QPI, the current research showed that microwave heating and boiling might be better heat treatment methods for QPI and would help the development of quinoa protein products.     

Gluten-free quinoa noodles: effects of intermediate moisture extrusion and soy protein isolates supplement on cooking quality and in vitro digestibility

Quinoa is considered as a superior gluten-free material due to its balanced composition of amino acids in protein and abundant nutrients. However, the processing behaviour of quinoa flour is limited by protein functional properties. In this study, twin-screw extrusion was used for the production of gluten-free quinoa noodles (GFQNs). Moisture was found to be closely related to the cooking quality and texture characteristics of extruded noodles by regulating the formation of starch gel. With this in concern, the moisture dose was optimised as 30%. Then, soy protein isolate (SPI) was supplemented into quinoa flour to improve the texture and cooking quality of GFQNs while decrease its in vitro starch digestibility. It was found that SPI could significantly reduce the cooking loss of GFQNs from 16.65% to 11.82% while increase the hardness of the noodles from 6.35 N to 7.99 N, and form a more porous structure as observed by SEM. Furthermore, the addition of SPI also delayed the in vitro hydrolysis rate of quinoa-based noodles, as shown by the significant decrease in rapid digestible starch around 8%. Therefore, quinoa–SPI mixture flour with the intermediate moisture extrusion showed prospective to develop low glycaemic index GFQNs.     

Effect of storage at 0 °C on mantle proteins and functional properties of jumbo squid

Effect of iced storage of jumbo squid mantle with fin on gelling capacity and changes in protein fractions and functional properties of jumbo squid mantle protein during storage at 0 °C were assessed. Most values of texture variables in gels did not significantly change during storage. On average, they were: strength 65.07 ± 4.71 N; elasticity 68.14 ± 5.3%, fracturability 52.97 ± 1.28 N and cohesiveness 36.6 ± 0.1%. Protein solubility increased more than 40%. Whippability increased during storage for 16 days at 0 °C (81–162%), as did foam stability (73–94%). Results suggest that iced squid mantle protein is a suitable ingredient for food products where these functional properties are desirable. Muscle fibres of squid mantle undergo various changes during storage. At 0 °C, they are disrupted, whereas at −20 °C, they aggregate and develop empty spaces in the tissue.     

藜麦全谷物粉对馕抗氧化性影响的研究

目的 为提高馕的抗氧化物质的含量和提高其抗氧化特性, 方法 通过添加不同量的杂粮谷物粉以增加馕的抗氧化物质的含量和提高其抗氧化特性,在单因素实验的基础,利用Box-Behnken试验优化馕的口感得分制备条件。结果 馕的最优工艺为藜麦全谷物粉添加10.34%、高粱粉添加11.41%、小米粉添加9.97%、酵母使用量为0.96%、水分加入量为51.81%、发酵时间为85.94 min, 在此条件下制备的复合谷物粉馕的感官评价平均得分为80.43, 黄酮含量为1.2 mg/g、多酚含量为61.26 mg/g, 分别比纯小麦粉馕的感官得分、黄酮和多酚含量提高了3.4%、9.1%和16.46%; DPPH●自由基清除率平均值为58.83%, ABTS●+自由基清除率平均值为51.58%, 还原力平均值为10.67 mg/g, 分别比纯小麦粉馕的DPPH●、ABTS●+自由基清除率和还原力提高了22.05%、15.39%和10%。结论 以藜麦全谷物粉、高粱粉和小米粉混粉制备馕, 可以显著提高其黄酮含量、多酚含量及其抗氧化性能。     

Enzyme activities in quinoa (Chenopodium quinoa)

The amylase, protease, cellulase and hemicellulase activities were determined in the flour of untreated quinoa seeds, and again after mechanical abrasion and after water and heat treatment to remove saponins. Optimum pH for amylase activity was approximately 5.0 and for protease activity it was 4.2
In comparison with a non-malted wheat flour, which generally would have a Braben-der unit (BU) reading of over 2000 in the Amylograph, values for quinoa were very low, indicating a high α-amylase activity. Mechanical abrasion, which removed about 18% of kernel weight, increased α-amylase and protease activities of the seeds because of removal of layers low in activity. Only toasting of seeds at 170°C after saponin removal reduced activities of these enzymes substantially.
Total amylase, cellulase and hemicellulase activities were highest in the unprocessed seeds. Activities decreased after mechanical abrasion of seeds. Heat treatment after saponin removal caused a further decrease in activity of these enzymes.     

Effect of roasting conditions on the antioxidant compounds of quinoa seeds

The effect of different roasting conditions on the antioxidant properties and the phenolic content of quinoa seeds was studied. Advanced and final products of the Maillard reaction were also quantified in order to evaluate the contribution to DPPH radical scavenging capacity and reducing power of samples. In general, response surface analysis showed significant increases in the phenolic content, the antioxidant activity and the level of Maillard reaction products (MRPs), mainly as processing temperature increased, while roasting time had a minor impact on these response variables. The highest antioxidant activity was achieved in extracts of quinoa seeds roasted at 190 °C for 30 min. Principal component analysis applied to the data suggested that MRPs had a greater contribution to antioxidant properties than phenolic compounds in the processed samples. These results demonstrated that roasted quinoa seeds/flour may be considered as a nontraditional ingredient with enhanced antioxidant capacity for the production of functional foods.     

Effect of storage conditions on nutritional quality and color characteristics of quinoa varieties

To maintain grain quality and prevent loss, effective storage systems are required. The aim of this study was to evaluate the effects of storage duration (0, 60, 120, 180, 240, 300, 360 days) and temperature (4, 10, and 25 °C) on proximate and nutritional components, and color properties of Mint Vanilla and Titicaca quinoa varieties. The results showed that the increase in storage duration and temperature leads to changes in the grain moisture, protein and ash contents, nutritional component and color properties. There was an increase in ash content at 25 °C, moisture content at 10 and 25 °C, and protein content at 4 °C in the stored grains compared with the grains on the initial of storage for Mint vailla variety. Whereas, there was an decrease in ash and protein content for all the temperature at the end of 360 days storage for Titicaca variety. Overall, there was a decrease (except Fe, Zn, Co, Ni, Cd and Pb) in the nutritional component of both quinoa varieties. L1, H° and WI values decreased, and a1, b1 and C1 values increased as a function of storage duration and temperature and showed some temperature-dependent degradation for both quinoa varieties.     

Protein deterioration and longevity of quinoa seeds during long-term storage

Seed protein stability and seed deterioration during storage were studied in seeds of two different quinoa (Chenopodium quinoa Willd.) cultivars, i.e., cv. Ollagüe and cv. Baer II. Germination and viability tests proved that cv. Baer II was more longevous than cv. Ollagüe. Protein insolubilisation was detected during storage and correlated with longevity. However, protein solubility was restored by priming in both cultivars, disregarding their germination capability. Extremely high contents of advanced glycation end-products (AGEs), assessed by carboxymethyllysine (CML) quantification, were obtained from stored seeds as viability was reduced; primed seeds showed slightly lower AGE content, indicating a strong association between quinoa seed ageing and Maillard products accumulation. High intensity fluorescence values were observed in seeds stored in the gene bank bearing 100% germination values, which indicate that the detection of fluorescence is not by itself an appropriate indicator of protein damage by Maillard-type product accumulation in quinoa seeds. This work establishes for the first time a direct association between seed viability and AGE accumulation, due to Maillard reaction, in quinoa seeds.     

Improvement of functional properties of acid-precipitated soy protein by the attachment of dextran through Maillard reaction

The functional acid-precipitated soy protein (SAPP)–dextran conjugate was prepared by dry-heated storage at 60 °C under 79% relative humidity (RH) for 5 days through Maillard reaction between the ε-amino of lysine in soy proteins and the reducing-end carbonyl residue in the dextran. The covalent attachment of dextran to SAPP was confirmed by SDS-polyacrylamide gel electrophoresis and gel filtration chromatography. Functional properties of soy protein depend on the structural and aggregation characteristics of their major components (storage globulins 7S and 11S). The conjugate seemed to be predominantly formed by 7S, and the acidic subunits of 11S in soy protein. The emulsifying properties of the SAPP–dextran conjugate were about four times higher than those of SAPP. The solubility of the protein was not enhanced as a result of preheating, but rather it was not decreased when the conjugated protein was heated at 90 °C for 20 min due to the presence of the polysaccharide. The excellent emulsifying properties of SAPP–dextran conjugate were maintained even at pH 3.0 and were further improved at pH 10.0. The object of Maillard reaction is to guarantee the suitable reaction degree, and the resulting soluble conjugate can have excellent emulsifying properties.     

Stability of protein digestibility and composition of cowpea (Vigna unguiculata L. Walp.) during sealed storage at different temperatures

Whole grains and flours of two cultivars of cowpea ( Vigna unguiculata ) were stored sealed at steady temperatures of 0, 20 and 55°C, and 11–13% moisture for 7 months. The pH, soluble sugars, free amino nitrogen, titratable acidity, and protein digestibility decreased at 55°C. The changes varied with cultivar and between the flours and the grains stored at 0 and 20°C. All changes, except titratable acidity in white cowpea flour, were strongly correlated with increasing storage temperature.     

Effect of quinoa,chia and millet addition on consumer acceptability of gluten-free bread

There is an increasing demand for gluten-free foods; however, standard gluten-free foods are deficient in nutrients. This study investigated the use of alternative grains (chia, millet and quinoa) in gluten-free breads to evaluate their sensory properties (fresh and following a partial bake method). A sensory trial (n = 98) asked participants to consider six fresh bread samples made from chia, millet and quinoa, using 9-point hedonic scales and check-all-that-apply. A second sensory trial (n = 89) was then completed using par-baked bread samples of the different formulations. The sensory properties and the acceptability of the bread were significantly affected by the chia and quinoa flour. The millet flour did not change the acceptability of the bread. Furthermore, the partial baking method (after 90 days of frozen storage) did not significantly affect the acceptability of the breads made with chia, millet and quinoa, but it did affect the acceptability of the control bread prepared with brown rice flour. Overall, millet flour could be incorporated into gluten-free breads made following a partial baking method without affecting consumer acceptability. Future studies should use a trained panel to evaluate how the breads differ based on the partial baking method.     

Effects of processing on the nutraceutical profile of quinoa

Quinoa flour was subjected to a variety of thermal processes. Both unprocessed and processed quinoa samples were subjected to successive extractions in methanol and ethyl acetate solvents. Effects of processing were gauged via comparison of HPLC chromatograms of the quinoa extracts. Quinoa flour subjected to processing via roasting and extrusion resulted in a significant impact on the chemical profile when compared to unprocessed quinoa flour. Steam pre-conditioning had minimal effects on the chemical profile of quinoa flour. Process-enhanced isolate from roasted and extruded quinoa possessed a molecular weight of 480 D, was dissolved in methanol and ethyl acetate, and possessed a NMR spectra reminiscent of a terpenoid compound. This research suggests that thermal processing of quinoa flour can result in degradation of saponin molecules. Saponin decomposition may influence sensory or pharmacological properties.     

Storability of Antimicrobial Chitosan-Lysozyme Composite Coating and Film-Forming Solutions

ABSTRACT:  Chitosan-lysozyme (CL) film and coating solutions were prepared aseptically by incorporating 60% lysozyme (w/w chitosan) into 3% chitosan solution. The solutions were stored at 10, 21, and 37 °C up to 6 mo for monthly evaluation of physicochemical and antimicrobial properties. Solutions were made into films at each sampling time to investigate lysozyme release, water solubility, water vapor permeability (WVP), tensile strength (TS), and elongation (EL) of the films. During the 6-mo storage, the pH and translucency of CL solutions did not change ( P > 0.05) and microorganisms were not detected with total aerobic count media. CL solutions became darker, with a more saturated yellow hue developing with increased storage time and temperature. Storage enhanced the antimicrobial activities of the solutions against E. coli and L. monocytogenes , and films made of solutions stored at 37 °C exhibited higher antimicrobial activities against these 2 pathogens than those stored at 10 and 21 °C. Increased water solubility and lysozyme release and decreased TS and EL were observed in films made from solutions stored at 37 °C. WVP was not significantly affected by storage temperature and time. These changes might be attributed to increased chitosan degradation by lysozyme hydrolysis at a higher storage temperature and longer storage time. Results indicated that with storage at 10 to 20 °C, premade CL solutions are stable and may be distributed as a commercial product for coating or film applications or both in different foods for at least 6 mo.     

Effect of processing on in vitro digestibility of protein and starch in quinoa seeds

The in vitro digestibility of protein in raw quinoa assessed by an enzymic method was 78%, significantly ( P > 0.01 ) lower than that of casein, 91%, and also somewhat lower ( P > 0.01) than that of the raw washed quinoa sample, 83%. the process used to remove the outer layers of the seeds containing saponins increased the protein digestibility significantly ( P > 0.01), by 7%. Heat treatments increased protein digestibility over that of raw quinoa samples. Only the cooked sample treated for 60 min presented a slightly lower protein digestibility, 77%, than those obtained for other heat-treated samples.
The temperature, time and moisture used in cooking and autoclaving of whole seeds of quinoa did not improve starch digestibility significantly. the digestibility of the starch in the raw and precooked samples was 72 and 77%, respectively, after drum drying and about 64% after extrusion in both cases. Precooking at 60°C for 20 min does not improve the digestibility of the quinoa starch.     

The effect of transglutaminase crosslinking on the rheological characteristics of heated peanut flour dispersions

ABSTRACT:  Peanut flour (PF) is a high-protein ingredient prepared after the partial extraction of oil from roasted peanut seed. Microbial transglutaminase (TGase) catalyzes protein crosslinking via acyl-transfer reactions, resulting in the modification of functional properties such as viscosity, gelation, solubility, and water holding capacity. This work was conducted to observe changes in rheological properties of PF dispersions in the presence and the absence of TGase and amidated pectin (AP). Dispersions were characterized across a range of conditions, including controlled heating and cooling rates under both large- and small-strain deformations. Gelation occurred at temperatures above 78 °C using PF dispersions treated with TGase compared to untreated dispersions devoid of the enzyme (about 68 °C). The addition of AP (0.5%) resulted in a general increase in viscoelasticity for all dispersions. AP addition also minimized the shift in gel point temperature caused by TGase polymerization reactions. High-molecular-weight polymers were formed in TGase-treated PF dispersions in both the presence and the absence of AP; however, polymer formation was more rapid in PF dispersions without AP. Ortho-phthaldialdehyde assays indicated about 40% protein coupling in PF dispersions treated with TGase compared to about 20% in those containing both AP and TGase. Collectively, these data suggest potential applications of TGase-treated PF dispersions, both in the presence and the absence of AP, for use in peanut-base food products, including protein bars, shakes, and value-added baked goods.     

Effect of Calcium Salts on the Properties of Proteins from Oil Sardine (Sardinella longiceps) During Frozen Storage

ABSTRACT:  The effect of calcium sulfate and calcium chloride on the enzymatic and structural properties of actomyosin isolated from sardine was investigated. Mince was prepared from sardine and different concentrations of calcium chloride and calcium sulfate were added to the mince and kept in frozen condition at −20 °C. The physico-chemical and functional properties of proteins from mince were analyzed as a function of time. The solubility of proteins decreased during storage. The reduction in solubility was less for samples treated with calcium chloride. However, sardine mince showed better functionality during storage in the presence of calcium compounds. The ATPase enzyme activity of actomyosin increased with increase in concentration of calcium and decreased after reaching the maximum value. ATPase activity of proteins from mince decreased during storage at low temperature. The reduction in ATPase activity did not correlate with the loss of functionality of proteins. SDS-PAGE did not reveal any major changes in the protein profile during storage as well as in the presence of different concentration of calcium compounds. The secondary structural content of actomyosin was not altered in the presence of both calcium chloride and calcium sulfate as evident from circular dichroic measurements.     

Composition and functional properties of raw and electron beam-irradiated Mucuna pruriens seeds

The proximate, nutritional and functional properties of raw and electron beam-irradiated (0–30 kGy) Mucuna seeds were investigated. Irradiation increased crude protein and crude carbohydrates significantly than crude lipid, crude fibre and energy. Raw seeds were rich in minerals and were not affected by irradiation except for magnesium and phosphorus. Amino acids of raw seeds were comparable to soyabean and FAO/WHO reference pattern and except for 30 kGy, no significant changes were seen in amino acid profile. Raw seeds were rich in unsaturated fatty acids and some of them decreased on irradiation, while linoleic acid steadily elevated (0–14.35 mg g⁻¹ lipid). In vitro protein digestibility was dose dependent and significantly increased up to 15 kGy. Water and oil absorption capacities and foaming capacity significantly increased on irradiation, while protein solubility decreased (15 and 30 kGy) with an improvement of gelation property of seed flour. The cooking time of seeds significantly reduced on irradiation.     

Influence of Salmon Provenance and Smoking Process on Muscle Functional Characteristics

ABSTRACT: Ocean-ranched and farm-reared Atlantic salmon were compared on the basis of compositional and functional/mechanical properties of the raw and the corresponding smoked muscle. Several procedures based on different salting methods (brine and dry salting) and smoking temperature (20 °C and 30 °C) were tested, as well as an electrostatic smoking method. Also, raw material samples were studied without and with frozen storage (-20 °C) for 30 d prior to salting/smoking, and the effect of frozen storage on the smoked muscle was evaluated. The electrostatic method induced considerably lower shear force values than the other smoking treatments. Ocean-ranched salmon were more susceptible to protein aggregation and loss of binding properties (water and fat) than farmed fish as a consequence of frozen storage of the raw material or smoking treatment.     

藜麦南瓜复合粉配方的优化

为开发藜麦即冲即食新产品,对炒制、蒸制、喷雾干燥不同制粉方式下藜麦的冲调性开展了研究。通过对藜麦粉的水溶性、吸水性、溶解性、润湿下沉性以及稳定性指数进行比较,选择冲调性好的藜麦粉与南瓜粉、木糖醇、奶粉、木薯变性淀粉、麦芽糊精进行复配。在单因素试验的基础上,采用响应面设计,以感官评分为响应值,对其配方进行了优选,并测定了成品的营养成分及流动性。结果表明,喷雾干燥制得的藜麦粉水溶性、吸水性、溶解性、润湿下沉性、稳定性指数分别为50.31%±0.56%、3.75%±0.19%、62.20%±2.71%、120.00±7.16 s、40.98%±4.41%,较炒制、蒸制冲调性好;藜麦南瓜复合粉的最佳配方为藜麦粉46.0%、南瓜粉22.0%、木糖醇22.0%、奶粉3.0%、木薯变性淀粉2.5%、麦芽糊精4.5%;成品中能量、脂肪、蛋白质、碳水化合物和钠分别为1595 kJ/100 g、3.8 g/100 g、9.14 g/100 g、75.6 g/100 g、111 mg/100 g,休止角为24°,流动性好。研究成果丰富了藜麦产品种类,为工业化生产提供了依据。