Characterization of Moringa oleifera leaf and seed protein extract functionality in emulsion model system

This study provides a comparative overview of Moringa oleifera leaf and seed protein extract (LPE and SPE, respectively) functionality in emulsions. Raw seed cake (RS) had more protein (45.8%) than raw leaf (RL) (27.4%). RL comprised higher polyphenol and flavonoid content than RS, Granny Smith apples, and Goji berries. Protein functionality data revealed that LPE had excellent solubility, and emulsifying properties than SPE at pH 7.0. In contrast, SPE had relatively strong surface hydrophobicity. At pH 7.0, leaf extract emulsions (LEE) possessed relatively small particle size distribution, strong negative charge, excellent stability, and minimum sedimentation velocity. On contrary, at pH 3.5, particle size, and velocity increased, contributing to monodisperse sedimentation. Seed extract emulsions (SEE) had an overall large particle size and demonstrated fast and extensive creaming and sedimentation at both pH conditions. Our findings indicate that M. oleifera leaf protein extracts have considerable potential for use in emulsion-based foods.     

云中漫步爱情厨房

自二十世纪70年代．法国的Masquelier教授从葡萄籽中提取出更高含量的OPC(原花青素)后，对其的抗氧化性和保健方面的研究就一直在进行着，并逐渐成为消费的关注热点。     

新型食品配料-葡萄籽提取物的发展

早在二十世纪80年代,美国普通消费者就开始认识和接受OPC,在由美国Whole Foods杂志组织的调查中,葡萄籽提取物被排在公众信赖和喜爱的植物型补充剂的前列.     

Rheological properties of Salecan as a new source of thickening agent

Salecan is a novel soluble glucan produced by Agrobacterium sp. ZX09, displaying the ability to inhibit pancreatic amylase and reduce postprandial glucose. The research here provides an investigation of the rheological properties of Salecan solution over a wide range of shear rate (0.001–1000 s⁻¹), frequency (0.1–100 rad/s), concentrations (0.3%, 0.5%, 1.0% and 1.5%), temperature (5–95 °C) and pH (1.0–13.0). The power law model well described the rheological behavior of the solutions, in the shear-thinning region, with high determination coefficients, R². Salecan solutions showed a non-Newtonian viscosity behavior at all concentrations and temperatures. The solutions exhibited excellent stability below 55 °C. Viscosities were not affected after being frozen (−20 °C). Over a wide pH range from 6.0 to 12.0, the viscosity almost kept invariant. With increasing frequency, the storage and loss moduli G′ and G″ of Salecan solution increased and complex viscosities decreased continuously, which showed an elastic behaviour. All data indicated that Salecan has excellent rheological properties and could be utilized in food industry as a new source of thickening agent.     

Extraction optimization of a hydrocolloid extract from cress seed (Lepidium sativum) using response surface methodology

Extraction conditions for maximum values of yield, viscosity and minimum protein content of hydrocolloid extract from Lepidium sativum seed were investigated using response surface methodology. A Central Composite Face Design (CCFD) with four independent variables: temperature (25–85 °C); pH (3–10); extraction time (10–25 min) and water to seed ratio (10:1–80:1) was used to study the response variables (yield, viscosity and protein content). Data analysis showed that all the variables significantly (p < 0.05) affected the extraction yield and viscosity, whereas the effect of water to seed ratio on protein content was not significant (p > 0.05). Applying a desirability function method the optimum parameters were: extraction temperature 35 °C, pH 10, water to seed ratio of 30:1 and an extraction time of 15 min. At this optimum point, apparent viscosity, yield and protein content were 0.2 Pa s, 6.46% and 0.57%, respectively. The experimental values were very close to the predicted values and were not statistically different (p > 0.05).     

A colored avocado seed extract as a potential natural colorant

There is an increasing consumer demand for and scientific interest in new natural colorants. Avocado (Persea americana) seed when crushed with water develops an orange color (= 480 nm) in a time-dependent manner. Heat treatment of the seed prevented color development, whereas the addition of exogenous polyphenol oxidase (PPO), but not peroxidase restored color development. Color development was also inhibited by the addition of tropolone, an inhibitor of PPO. Color formation resulted in a decrease in the concentration of polyphenols indicating utilization for color formation. The orange color intensified as the pH was adjusted from 2.0 to 11.0, and these changes were only partially reversible when pH was adjusted from 7.5 to 11.0 in the presence of oxygen, but completely reversible when the pH was changed in the absence of oxygen. The color was found to be stable in solution at -18 °C for 2 mo. These results suggest that the avocado seed may be a potential source of natural colorant, and that color development is PPO-dependent. PRACTICAL APPLICATION: There is growing public and scientific interest in the development of natural alternatives to synthetic colorants in foods. Extracts of turmeric, paprika, and beets are examples of food-derived natural colorants. Avocado seeds, which represent an under-utilized waste stream, form a stable orange color when crushed in the presence of air. Our data indicate that avocado seed represents a potential source of new natural colorants for use in foods.     

Rheological properties of Lepidium sativum seed extract as a function of concentration, temperature and time

The seeds of Lepidium sativum (Garden Cress) were selected as a new source of hydrocolloid and its chemical composition and molecular parameters were determined. The macromolecular component of the extract had a molecular weight of 540 kDa, and was nearly as rigid as xanthan with regard to chain conformation. The main rheological features were investigated as a function of shear rate, concentration and temperature. The extract exhibited strong shear-thinning behaviour, which was even more pronounced than for xanthan. An increase in concentration or temperature led to an increase in pseudoplasticity. The Arrhenius model was applied to the temperature dependence of viscosity, and the activation energy (E_a) was found to decrease with increasing concentration. The extract solutions showed thixotropic behaviour at all the concentrations and temperatures studied, and the first-order stress decay model with a non-zero equilibrium stress fairly described the time-dependent behaviour. The rheological characteristics found indicated a potential application of the extract as a novel thickener.     

Full-fat sunflower seed as a protein source for broiler chicks

The protein quality of hulled full-fat sunflower seed (HFFSS) was evaluated and compared to that of soyabean meal in two experiments with broiler chicks. In the first experiment, PER and NPR indexes were determined. The results showed that, when fed as the sole source of dietary protein (90 g crude protein kg⁻¹ diet), the performance as well as PER and NPR values of chicks fed HFFSS were much poorer than those of chicks fed soyabean meal. The protein quality of HFFSS was improved greatly by lysine supplementation. The PER and NPR values for HFFSS supplemented with 0.2 and 0.4% of L -lysine equalled and even became superior to those estimated for soyabean. In the second experiment, apparent and true ileal digestibilities of nitrogen and amino acids were calculated. The apparent but not the true digestibility of the mean of amino acids was significantly lower (P < 0.01) in HFFSS than in soyabean meal (0.838 vs 0.902 and 0.932 vs 0.957, respectively). The results also showed that lysine from HFFSS was less digestible than that from soyabean meal, the apparent as well as the true digestibility values being lower in the former. © 1999 Society of Chemical Industry     

Scallops as a new source of food protein: high-intensity ultrasonication improved stability of oil-in-water emulsion stabilised by myofibrillar protein

In this study, the effect of high-intensity ultrasound (HIUS) (200 and 400 W for 0, 5, 10 and 15 min respectively) on conformational changes, physicochemical, rheological and emulsifying properties of scallop (Patinopecten yessoensis) myofibrillar protein (SMP) was investigated. HIUS-treated SMP had lower α-helix content and higher β-sheet content compared with the native SMP. HIUS treatment induced the unfolding of SMP and increased the surface hydrophobicity. The particle size of SMP decreased and the absolute zeta-potential increased after ultrasonication, which in turn increased the solubility of SMP. The conformational changes and the improvement of physicochemical properties of SMP increased the ability for SMP to lower the interfacial tension at the oil–water interface and increased the percentage of adsorbed protein. As a result, the emulsifying properties, rheological properties of SMP and storage stability of emulsions were also improved. In conclusion, HIUS treatment has future potential for improving the emulsifying properties of SMP.     

Physical properties of hydrocolloid wet glues

The potential properties of 26 gums to serve as a basis for wet-gum glues were studied. Preliminary tests revealed that only 13 of these, namely gum talha, gum ghatti, gum karaya, gum tragacanth, arabinogalactan, dextran, pectin, tapioca-dextrin, carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxypropyl cellulose (HPC), hydroxypropylmethyl cellulose (HPMC) and carbopol, can serve as bioadhesives in hydrophilic systems. Wet glues were produced from these hydrocolloids. They were tested over a wide range of loadings, i.e. 10–75% (wlw). The color and pH of each glue were determined. Their ability to adhere to two separate films—cellulose acetate and a skin-surface model—was studied. After checking the performance of the glues by peel testing, seven gums were chosen for further study. Adhesion was evaluated by tensile-bond and lap-shear tests. The deformation rate, the adhesive layer thickness, the degree of hydration of the films and glue, the length of drying time, and the type of hydrocolloid used were found to influence the wet glue bond strength.     

光特征在食品乳液中的表征和应用

介绍了其在乳液中的表征和应用,以期能对乳液外观的设计有更加系统地考量。     

Physico-mechanical properties of chitosan films with carvacrol and grape seed extract

The physico-mechanical properties of 3 films composed by carvacrol, grape seed extract (GSE) and chitosan in different proportions were studied. The films, prepared by solvent casting technique with the following compositions of the casting solutions in carvacrol, GSE and chitosan: film-1: 9.6 ppm–684 ppm–1.25% w/v, film-2: 60 ppm–400 ppm–1.2% w/v and film-3: 90 ppm–160 ppm–1.24% w/v and were compared to a control (1.25% w/v chitosan) film. Mechanical, structural, barrier and colour properties of the films were evaluated. Film-3 presented the lowest water vapour and carbon dioxide permeabilities (WVP and CO₂P) and tensile strength (TS) values and the highest oxygen permeability (O₂P), whereas film-1 presented the highest water content and the lowest crystallinity, CO₂P, TS and luminosity. These results suggest that in the range studied, carvacrol and GSE affect the film structure and its mechanical properties due to hydrophilic (GSE) and hydrophobic (carvacrol) compounds. This work will help the development of edible films, based on physico-mechanical properties, contributing to food preservation and shelf-life extension.     

Physicochemical aspects of hydrocolloid extract from the seeds of Lepidium sativum

Acid equivalent weight, intrinsic viscosity and FT‐IR measurements have demonstrated a polyelectrolyte nature to Lepidium sativum seed extract. The polyelectrolyte nature relates to the carboxyl groups carried by galacturonic acid and glucuronic acid unit. The seed extract exhibited pronounced shear thinning in steady shear rheology and a weak gel type behaviour in dynamic rheology when the concentration is high i.e. > 1%. Such behaviour suggests the ability of L. sativum seed extract to structure a liquid, thus showing the possibility of applying it as a novel thickener and stabiliser in aqueous systems. The characteristic could be due to a strong tendency of molecular association of L. sativum seed extract as found for high M/G ratio galactomannans, and possibly also the enhanced macromolecular entanglement due to relatively rigid chain conformation. Temperature dependence study showed that the rheological properties of L. sativum structured solution is stable against temperature variation.     

大麦饮料乳状液的稳定性

以大麦为原料,经过烘焙,粉碎,酶解后,加入白砂糖,乳化剂,亲水胶体,稻米油,来制备大麦饮料乳状液,通过单因素确定最佳的乳化剂、亲水胶体,在单因素实验的基础上,以电位、乳化稳定系数ESI、多分散系数PDI为响应值,利用响应面优化方法(RSM)中的Box-Behnken方法确定最优的配方比,得到的最优条件为:柠檬酸单甘脂0.2%,SMS 0.1%,稻米油0.9%,黄原胶0.07%,卡拉胶0.3%,此时的电位为-43.5 mV,ESI为100%,PDI为0.419。验证试验的电位为(-42.7±0.9)mV,ESI为(100±0.0)%,PDI为0.414±0.023。     

Characterizing the gloss properties of hydrocolloid films

Hydrocolloid films were prepared by two methods, namely dehydration of thin layers of gels and of gum solutions. Gelatin gel films containing greater amounts of dry matter than all other prepared films provided by far the highest gloss values. Increase in gelatin concentration in the gels resulted in an increase in the mean gloss of the dry films in a linear fashion. Roughness measurements and scanning electron microscope (SEM) micrographs indicated that the gelatin films possessed very smooth surfaces. Similar to gelatin, increase in concentration of gellan resulted in an increase in gloss of resultant films. In direct contrast, mean gloss of both agar and agarose gel films decreased with increasing gel concentration. These trends may be due to the increase in roughness of films with increasing gel concentration, which in the case of agar was also noticeable in the SEM micrographs. Xanthan films provided the most glossy appearance of those prepared by drying of gum solutions, followed closely by alginate. Both exhibited the same trend of mean gloss increasing with gum concentration, similar to gelatin. In both instances, this behaviour could not be related to roughness, which also increased with gum concentration.     

Lupine,a source of new as well as hidden food allergens

The present review summarizes current knowledge about lupine allergy, potential sensitization routes, cross‐reactions between lupine and other legumes, and the respective IgE‐binding proteins. Since the 1990s, lupine flour is used as a substitute for or additive to other flours, mostly wheat flour, in several countries of the EU. In 1994, the first case of an immediate‐type allergy after ingestion of lupine flour‐containing pasta was reported. Since then, the number of published incidents following ingestion or inhalation of lupine flour is rising. So far, the Lupinus angustifolius β‐conglutin has been designated as the allergen Lup an 1 by the International Union of Immunological Societies Allergen Nomenclature Subcommittee. Initially, publications focussed on the fact that peanut‐allergic patients were at risk to develop anaphylaxis to lupine due to cross‐reactivity between peanut and lupine. At present, however, the ratio between cases of pre‐existing legume allergy (mostly peanut allergy) to de novo sensitization to lupine seed is nearly 1:1. Although in December 2006, lupine and products thereof were included in the EU foodstuff allergen list according to the Commission Directive 2006/142/EC amending Annex IIIA of Directive 2000/13/EC in order to prevent severe reactions caused by “hidden food allergens”, the majority of patients and medical personnel are still not aware of raw lupine seed as potentially dangerous food allergen.     

一种新资源油脂——茶叶籽油的研究现状分析

茶叶籽油是以山茶科植物茶树成熟种子——茶叶籽为原料制备的食用植物油,具有较高的营养价值与独特的生理功能,是一种新开发的可食用植物油.茶叶籽油中不饱和脂肪酸含量较高,亚油酸含量高于油茶籽油及橄榄油,且含有多种功能性成分,在高级食用油、化妆品、医药等行业具有广阔的市场前景.总结分析了目前我国茶叶籽油的提取工艺、理化特性、脂肪酸组成、活性成分及保健功能等方面的研究现状,为茶叶籽油的进一步开发应用提供参考,以期促进我国茶叶籽油产业的发展.