Functional properties of protein concentrates and isolates produced from cashew (Anacardium occidentale L.) nut

Protein isolates and concentrates were obtained from defatted cashew nut powder by two methods: alkaline extraction-isoelectric precipitation (IP) and alkaline extraction-methanol precipitation (MP). The functional properties of cashew nut protein isolates, concentrates and powder were significantly different (p < 0.05). Cashew nut protein isolate (CNPI) had higher water and oil absorption capacities (2.20 ml/g and 4.42 ml/g, respectively), emulsifying stability index (447%), foam capacity and stability (45% and 55%, respectively), and least gelation capacity (13.5%) than cashew nut protein concentrate (CNPC), which was also higher than that of defatted cashew nut powder (DCNP). However, emulsifying activity index (12.45%) and bulk density (0.31) of CNPI were lower than that of CNPC, which were also lower than that of DCNP. The water solubility of CNPI (95%) and CNPC (95%) was not significantly different (p > 0.05) among the samples, but was significantly different (p < 0.05) from that of DCNP (75%). The CNPI, CNPC and DCNP showed decreasing solubility with decreasing pH, with the minimum solubility being observed at a pH range of 4.0–4.5, confirming the isoelectric point of cashew proteins. However, higher water solubility, emulsifying activity, and foaming property were observed at an alkaline pH than at an acidic pH in all samples.     

腰果全粉微胶囊化工艺及其性质结构的表征

以腰果为主要原料研制微胶囊化腰果全粉,优化生产工艺,并对产品的理化性质进行表征。结果显示,乳化剂配比单双甘脂蔗糖酯(质量比)为12时乳化稳定性最好,乳化剂添加量1.5%最为合适,芯壁比(质量比)以11为最佳,最佳固形物含量为25%。微胶囊基本成分为蛋白质12.94%、水分2.38%、碳水化合物61.57%、灰分2.45%、脂肪20.66%。微胶囊包埋率为94.23%、密度为0.68g/cm3、自流角为35.45°、溶解度为92.91%、吸湿性为0.77%。复原乳乳化效果好,溶液较为稳定,粒径主要在353.3nm左右。扫描电镜测定结果显示:腰果微胶囊颗粒为饱满的球形,分布均匀,多数直径处于25μm左右,包埋效果良好。     

Physicochemical and functional properties of full fat and defatted cashew kernel flours

Full fat and defatted cashew kernel flours were prepared and analysed for their physicochemical and functional properties. There were significant increase in protein and carbohydrate contents of the flour as a result of defatting. The defatted flour possessed higher Ca, P, Na and K contents. It had improved gel strength, foaming and emulsion properties. Foam capacity for the full fat and defatted flours increased from 42% to 50% and 55% to 57% with increased NaCl concentration up to 0.25 and 0.05  m , respectively. The foam capacity and stability of the flours were also pH dependent. The emulsion activity and stability of both flours decreased with increasing NaCl concentration. Minimum and maximum protein solubility were at pH 4 and 8, respectively for the full fat and defatted flours. These results suggest that defatted cashew flour may have potential application as a functional ingredient and as a supplement in foods.     

腰果蛋白的功能特性研究及其氨基酸组成分析

采用碱提法最优条件提取并酸沉得到腰果蛋白,研究了p H和温度对腰果蛋白的溶解性、起泡性及起泡稳定性、乳化性及乳化稳定性、持油性等功能特性的影响,并分析了腰果蛋白的氨基酸组成。结果表明:腰果蛋白的溶解性随p H的增加呈先降低后升高的趋势,在p H4附近溶解度最低,仅为15.90%。起泡性和乳化性随p H的变化曲线与溶解度曲线一致,在p H10时起泡性和乳化性最好,分别为13.92%、24.70 m2/g。腰果蛋白的起泡稳定性随p H的增加而逐渐增加,在p H8时达到最大为9.42%,而后趋于稳定。在碱性环境中,腰果蛋白会表现出较好的乳化稳定性,并且在80℃时其持油性最佳,为2.84 g/g。氨基酸分析表明,腰果蛋白中含有17种氨基酸,其中7种是人体必需氨基酸,含量皆高于FAO/WHO/UNO成人推荐标准,赖氨酸为第一限制性氨基酸,谷氨酸和精氨酸含量最高,分别为22.46%和9.02%。      

In vitro evaluation of cashew nut shell liquid as a methane-inhibiting and propionate-enhancing agent for ruminants

Cashew nut shell liquid (CNSL) containing antibacterial phenolic compounds was evaluated for its potency as a feed additive for ruminants. In experiment 1, ruminal responses to CNSL supplementation were assessed using a batch culture system. Rumen fluid from cattle was diluted with artificial saliva and incubated for 18 h in a batch culture with a mixed diet containing a 30:70 hay:concentrate diet to which raw or heated CNSL was added at a final concentration of 500 μg/mL. In experiment 2, a Rusitec, using rumen fluid from the same cattle, was operated over a period of 7 d during which only raw CNSL was tested at concentrations of 0, 50, 100, or 200 μg/mL, and variations in fermentation and bacterial population were assessed. In experiment 3, a pure culture study was conducted using selected bacteria to determine their susceptibility to CNSL. In experiment 1, methane production was inhibited by raw CNSL (56.9% inhibition) but not by heated CNSL. Total volatile fatty acid concentration was not affected, whereas increased concentrations of propionate and decreased concentrations of acetate and butyrate were observed using either raw or heated CNSL. These changes were more obvious when raw CNSL was tested. In experiment 2, raw CNSL inhibited methanogenesis and increased propionate production in a dose-dependent manner, showing maximum methane inhibition (70.1%) and propionate enhancement (44.4%) at 200 μg/mL supplementation. Raw CNSL increased total volatile fatty acid concentration and dry matter digestibility. Raw CNSL also appeared to induce a dramatic shift in the population of rumen microbiota, based on decreased protozoa numbers and changes in quantitative PCR assay values for representative bacterial species. In experiment 3, using pure cultures, raw CNSL prevented the growth of hydrogen-, formate-, and butyrate-producing rumen bacteria, but not the growth of bacteria involved in propionate production. Based on these data, raw CNSL, rich in the antibacterial phenolic compound anacardic acid, is a potential candidate feed additive with selective activity against rumen microbes, leading to fermentation that results in decreased methane and enhanced propionate production.     

一种全自动腰果脱壳机的脱壳试验研究

为了进一步提高腰果脱壳机的脱壳效果,分别研究了推果速度、切刀装置中弹簧压缩距离及进果时腰果的状态等因素对脱壳过程中整仁率、滑果率及躺果率的影响。结果表明:推果速度对腰果脱壳机的脱壳效果(整仁率、滑果率及躺果率)影响极显著(P0.01);弹簧压缩距离对腰果脱壳过程中整仁率的影响极显著(P0.01),对滑果率及躺果率影响不显著(P0.05);进料时腰果的状态对脱壳过程中整仁率和滑果率影响极显著(P0.01),对躺果率影响不显著(P0.05);当刀口距离9.1 mm,推果速度19.8r/min,弹簧压缩距离16.70mm,采用方式a1进果时,整仁率为69.76%。     

Antioxidative and functional properties of protein hydrolysate from defatted skipjack (Katsuwonous pelamis) roe

Antioxidative and functional properties of protein hydrolysate from defatted skipjack (Katsuwonous pelamis) roe, hydrolysed by Alcalase 2.4 L (RPH) with different degrees of hydrolysis (DH) at various concentrations were examined. As DH increased, the reduction of DPPH, ABTS radicals scavenging activities and reducing power were noticeable (p < 0.05). The increases in metal chelating activity and superoxide scavenging activity were attained with increasing DH (p < 0.05). However, chelating activity gradually decreased at DH above 30%. All activities except superoxide anion radical scavenging activity increased as the concentration of hydrolysate increased (p < 0.05). Hydrolysis using Alcalase could increase protein solubility to above 80% over a wide pH range (2–10). The highest emulsion ability index (EAI) and foam stability (FS) of hydrolysates were observed at low DH (5%) (p < 0.05). Concentrations of hydrolysates determined interfacial properties differently, depending on DH. The molecular weight distribution of RPH with 5%DH (RPH5) was determined using Sephadex G-75 column. Two major peaks with the molecular weight of 57.8 and 5.5 kDa were obtained. Fraction with MW of 5.5 had the strongest metal chelating activity and ABTS radical scavenging activity. The results reveal that protein hydrolysates from defatted skipjack roe could be used as food additives possessing both antioxidant activity and functional properties.     

Extraction of proteins from slaughterhouse by-products: Influence of operating conditions on functional properties

This study investigated the extraction and functional properties of proteins from slaughterhouse by-products: pork lungs, beef lungs and mechanically deboned chicken meat (MDCM). The extraction yield was investigated as a function of pH, temperature and time. Membrane technology was used for purification of proteins from pork and beef lungs, while for MDCM a method based on PI was applied. In the three cases, yields of protein recovery were between 48 and 55% (w/w). The functional properties of the protein concentrates were compared to those of some commercial ingredients. Proteins from pork lungs and MDCM exhibited better gelling properties than egg white and beef plasma, while beef and pork lungs displayed very good emulsifying properties, similar to Na-caseinates. As the methods developed are easy to scale-up, the use of by-product proteins at industrial scale appears to be an interesting opportunity to obtain added value slaughterhouse by-products.     

Effects on enteric methane production and bacterial and archaeal communities by the addition of cashew nut shell extract or glycerol—An in vitro evaluation

The objective of the study was to evaluate the effect of cashew nut shell extract (CNSE) and glycerol (purity >99%) on enteric methane (CH₄) production and microbial communities in an automated gas in vitro system. Microbial communities from the in vitro system were compared with samples from the donor cows, in vivo. Inoculated rumen fluid was mixed with a diet with a 60:40 forage:concentrate ratio and, in total, 5 different treatments were set up: 5 mg of CNSE (CNSE-L), 10 mg of CNSE (CNSE-H), 15 mmol of glycerol/L (glycerol-L), and 30 mmol of glycerol/L (glycerol-H), and a control without feed additive. Gas samples were taken at 2, 4, 8, 24, 32, and 48 h of incubation, and the CH₄ concentration was measured. Samples of rumen fluid were taken for volatile fatty acid analysis and for microbial sequence analyses after 8, 24, and 48 h of incubation. In vivo rumen samples from the cows were taken 2 h after the morning feeding at 3 consecutive days to compare the in vitro system with in vivo conditions. The gas data and data from microbial sequence analysis (454 sequencing) were analyzed using a mixed model and principal components analysis. These analyses illustrated that CH₄ production was reduced with the CNSE treatment, by 8 and 18%, respectively, for the L and H concentration. Glycerol instead increased CH₄ production by 8 and 12%, respectively, for the L and H concentration. The inhibition with CNSE could be due to the observed shift in bacterial population, possibly resulting in decreased production of hydrogen or formate, the methanogenic substrates. Alternatively the response could be explained by a shift in the methanogenic community. In the glycerol treatments, no main differences in bacterial or archaeal population were detected compared with the in vivo control. Thus, the increase in CH₄ production may be explained by the increase in substrate in the in vitro system. The reduced CH₄ production in vitro with CNSE suggests that CNSE can be a promising inhibitor of CH₄ formation in the rumen of dairy cows.     

Amino acid profile,protein digestibility,thermal and functional properties of Conophor nut (Tetracarpidium conophorum) defatted flour,protein concentrate and isolates

Functional properties, amino acid compositions, in vitro protein digestibility, electrophoretic and thermal characteristics of conophor defatted flour (CDF), conophor protein concentrate (CPC), isoelectric protein isolate (CII) and neutral protein isolate (CNI) were evaluated. The isolates (CII and CNI) showed significantly lower (P < 0.05) water and oil absorption capacities, emulsifying and gelling capacities, but higher emulsion stability and foaming capacity. In vitro protein digestibility, enthalpy and denaturation temperature varied between 52.28% and 73.4%, 1.62–4.04 J g^?1 protein and 79.7–89.3 °C, respectively. The native proteins were comprised of subunits with molecular weights ranging between 15.3 and 129.3 kDa. The major amino acids in all the samples were aspartic acid, glutamic acid and arginine, whereas the percentages of essential amino acids in CDF, CPC, CII and CNI were 39.35%, 40.46%, 44.54% and 46.04%, respectively. Conophor protein products could be used as functional ingredients in food formulations and for enriching low quality protein diets.     

Emulsifying properties of chickpea protein isolates: Influence of pH and NaCl

Structure and emulsifying properties of chickpea protein isolates (CPI) as a function of protein concentration, oil volume, pH and ionic strength were studied. The optimum protein concentration 2 g l⁻¹ used to determine the emulsifying properties was obtained. Emulsifying activity index (EAI) increased from 244 to 376 m² g⁻¹ with pH from 3.0 to 11.0 except the protein isoelectric point (pI 5.0), where the EAI was 20 m² g⁻¹ and emulsion droplet size was the largest. At lower ionic strengths (0.0–0.1 M NaCl, pH 7.0), EAI decreased from 253 to 72.4 m² g⁻¹; however, it increased from 72.4 to 231.4 m² g⁻¹ at higher ionic strengths (0.1–1.0 M NaCl). A positive relation between EAI and surface hydrophobicity (S₀) of CPI at various ionic strengths was obtained, while EAI was independent of S₀ under different pH values. α-Helix was the major configuration of CPI at the pI or lower ionic strength.     

Effects of succinylation and deamidation on functional properties of oat protein isolate

The effects of two different modification methods (deamidation and succinylation) on the functional properties (solubility, water- and oil-binding capacity, foaming capacity and stability, emulsion activity and stability) of oat protein isolates were evaluated. Protein isolates extracted from defatted oat flour at alkaline pH were acylated by 0.20 g/g of succinic anhydride. The protein isolate was also modified using a mild acidic treatment (HCl, 0.5 N). Succinylation and deamidation improved solubility and emulsifying activity of the native protein isolate. Foaming capacity of oat protein isolate increased after deamidation, whereas succinylation decreased it. The deamidated and succinylated proteins had lower foam and emulsion stabilities than had their native counterpart. Water- and oil-binding capacity, in both modified oat proteins, was higher than those of the native oat protein isolate.     

槟榔籽中抗氧化活性物质的分离与结构分析

为了研究槟榔籽中的抗氧化活性物质,通过柱色谱法分离纯化槟榔籽乙醇提取物,结合抗氧化活性筛选,分离得到槟榔籽中主要的抗氧化活性物质Fr-4。利用高效液相色谱分析其纯度,经波谱分析确定该物质为表儿茶素。     

Influence of the extent of enzymatic hydrolysis on the functional properties of protein hydrolysate from grass carp (Ctenopharyngodon idella) skin

Protein hydrolysates from grass carp skin were obtained by enzymatic hydrolysis using Alcalase^®. Hydrolysis was performed using the pH-stat method. The hydrolysis reaction was terminated by heating the mixture to 95 °C for 15 min. At 5.02%, 10.4%, and 14.9% degree of hydrolysis (DH), the hydrolysates were analyzed for functional properties. The protein hydrolysates had desirable essential amino acid profiles. Results demonstrated that the hydrolysates had better oil holding and emulsifying capacity at low DH. The water holding capacity increased with increased levels of hydrolysis. Enzymatic modification was responsible for the changes in protein functionality. These results suggest that grass carp fish skin hydrolysates could find potential use as functional food ingredients as emulsifiers and binder agents.     

Effects of protein solubilisation and precipitation pH values on the functional properties of defatted wheat germ protein isolates

Wheat germ protein isolates were prepared from defatted wheat germ flour using alkaline solubilisation and acid precipitation. A central composite design with two independent variables (solubilisation pH and precipitation pH) and bivariate correlations was selected for the correlation analysis of the protein separation conditions and the functional properties. The results showed that the protein yield (Y) and functional properties of isolates, such as water absorption (WA) and fat absorption (FA), were sensitive to both solubilisation pH and precipitation pH, whereas the emulsification was sensitive to only solubilisation pH. Emulsifying activity (EA) and FA of isolates showed a high positive correlation with yield. Gel electrophoresis analysis of protein fractions gave evidence to the compositional changes between proteins isolated under different conditions, highly alkaline conditions result in the degradation of protein chains and formation of toxic compounds. Surface hydrophobicity suggested that proteins tend to be more denatured when solubilised at highly alkaline conditions. These conformational and compositional changes due to different protein separation conditions have contributed to the changes in functional properties of protein isolates.     

Functionality of native and denatured cashew nut kernel protein isolates at isoelectric pH as a function of salt concentration

The reduced solubility of proteins near the isoelectric pH limits their use in food formulations whose pH lies in the range 5.0–6.0 because of poor functionality. In the present study, the effect of salt on the functionality of native and denatured cashew nut kernel protein isolates at the isoelectric pH was investigated. Both isolates showed improvement in their functional properties, but the improvement was greater for the denatured protein isolate. The solubilities of denatured and native protein isolates at the isoelectric pH increased from 26.4 g l^?1 and 64 g l^?1, respectively, without salt to maxima of 363 and 308 g l^?1, respectively, at 0.75 M salt concentration. The water binding capacity of the isolates increased with increase in NaCl concentration from 1.70 ml g^?1 to 1.77, 1.82, 1.92 and 2.2 ml g^?1 for denatured protein isolate and from 1.45 ml g^?1 to 1.65, 1.69, 1.82 and 1.97 ml g^?1 for native protein isolate at 0.25, 0.50, 0.75 and 1.0 M salt concentrations, respectively. When the properties of the isolates in 0.75 M NaCl solutions were compared with those in salt‐free water there were 15% and 116% increases in emulsifying capacity, 40‐fold and 45‐fold increases in emulsifying activity and 4.6‐fold and 40‐fold increases in emulsion stability for native and denatured protein isolates, respectively, whilst the corresponding foaming capacities increased from 4 to 5.5 and 0 to 8.9 ml g^?1 protein. Statistically, no difference in the foaming capacity of either of the isolates was observed above 0.5 M NaCl. The foam stability also exhibited similar behaviour. Copyright © 2004 Society of Chemical Industry     

Effect of pH and NaCl/CaCl2 on the solubility and emulsifying properties of sweet potato protein

BACKGROUND: The effects of NaCl and CaCl₂ on the solubility and emulsifying properties, namely emulsifying activity index (EAI) and emulsion stability index (ESI) of sweet potato proteins (SPPs) at pH 1–10, were investigated. RESULTS: At lower NaCl (0.1 mol L^?1) and CaCl₂ (0.05 mol L^?1) concentrations, the solubility profiles of the SPPs were very similar to those in distilled water, and the lowest solubility occurred at pH 4. Increased NaCl and CaCl₂ concentration resulted in lower SPP solubility in most of the pH studied (P < 0.05). At pH < 3, NaCl improved the EAI of SPP while at pH > 7 it reduced the EAI of the SPP (P < 0.05). Moreover, addition of NaCl also resulted in reduction of ESI of the SPP in most of the pH studied (P < 0.05). On the other hand, the presence of 0.2 mol L^?1 CaCl₂ rendered the EAI and ESI of the SPPs independent of the influence of pH. CONCLUSION: The present studies show that pH and salts modified the emulsifying properties of the SPPs, and CaCl₂ at a certain concentration could be used to improve the emulsifying properties of the protein. Copyright © 2008 Society of Chemical Industry     

Chemical compositions,functional properties,and microstructure of defatted macadamia flours

The objective of this research was to study the chemical compositions, functional properties, and microstructure of partially defatted flours (PDF, 12–15% fat, dry basis (db)) and totally defatted flours (TDF, 1% db fat) from three macadamia cultivars, PY 741, DS 344, and DS 800, grown in Northern Thailand. The defatted flours were high in protein (30.40–36.45% db) and carbohydrate (49.29–57.09% db). For each macadamia cultivar, while emulsion activities and emulsion stabilities of the TDF tended not to be different from those of the PDF (p > 0.05), TDF had significantly greater water absorption capacities (WAC), oil absorption capacities and foaming capacities (FC), but had significantly lower foaming stability (FS) than the PDF (p ? 0.05). The TDF from PY 741 cultivar possessed the highest WAC and FC but the lowest FS. The variation in the functional properties of the defatted flours could mainly arise from the difference in the quantity and characteristics of the proteins in the flours. Structure determination of macadamia flours showed that the proteins bodies and starch granules were embedded in kernel tissues. The starch granules were oval and approximately 10 μm in diameter.     

The effect of starch isolation method on physical and functional properties of Portuguese nut starches. II. Q. rotundifolia Lam. and Q. suber Lam. acorns starches

A new starch was isolated from fruits of two acorn species, Quercus rotundifolia and Quercus suber by alkaline (A3S) and enzymatic (ENZ) methods and physical and functional properties were studied. The isolation method induced changes in most of those properties in the isolated starches, mainly in resistant starch content, syneresis, pasting, thermal and rheological properties. Isolated acorn starches presented high amylose content (53–59%) and resistant starch content (30.8–41.4%). Acorn starches showed limited and similar solubility values and swelling power values, showing a gradual increase from 60 °C to 90 °C. The pasting temperatures ranged from 67.5 to 72.0 °C and pastes did not present breakdown, which is suggestive of a high paste stability of acorn starches during heating. At ambient temperature the turbidity and syneresis values were low, but when held at freezing temperatures the syneresis significantly increased. Thermal analysis revealed that the acorn starches easily undergo transition phenomena as shown by the low T_o and enthalpy values (4.1–4.3 J/g), these effects were more evident in starches isolated by ENZ method. Pastes are more elastic than viscous and form strong gels after cooling. Q. suber starch was shown to be more sensitive to the effect of isolation method. Generally, starch isolated by enzymatic method presented less interesting functional properties, since this isolation procedure greater affected the raw structure of starches.