Lactulose as a food ingredient

Lactulose is a synthetic ketose disaccharide that can be obtained from lactose by different methods of synthesis. Chemical methods are based on the isomerization of lactose in the presence of basic catalysts and enzymatic methods using lactose as a galactose donor and fructose as an acceptor. The prebiotic properties of lactulose have been known for more than 50 years and numerous studies have confirmed several health benefits of lactulose as a food ingredient, including selective stimulation of intestinal flora, laxative effect and improvement of calcium absorption. Its use in fermented milk manufacture may reduce the incubation period and favour the growth of bifidobacteria. The synthesis of lactulose‐derived oligosaccharides may provide a new group of prebiotics with properties complementary to those of native lactulose. Copyright © 2009 Society of Chemical Industry     

Characterisation of dietary fibre components in rye products

In this study, dietary fibre (DF) was characterised in rye products from a local supermarket. Soft breads generally had lower DF contents (8–18%) than had crisp breads (13–20%) due to high inclusion of wheat flour. For some products, the labelled DF values contained fructan, but others did not. However, for most products, the DF values analysed exceeded those declared. Arabinoxylan (AX) and fructan were generally the main DF components in the products, followed by cellulose and resistant starch, β-glucan, Klason lignin and arabinogalactan. In the soft breads, cellulose and resistant starch concentrations were relatively high, due to significant formation of resistant starch. During bread manufacturing, the molecular weight of β-glucan was highly degraded, while that of AX was more resistant. Extruded products had the highest β-glucan extractability and the extracted β-glucan retained its molecular weight most, which may be of nutritional significance. In rye milling fractions, about 50% of the fructan content analysed had a degree of polymerisation below 10, i.e. it comprised oligosaccharides. The crisp breads produced without yeast had the highest DF and fructan contents and the highest proportion of low-molecular weight fructan. These results indicate that, during bread-making, the low-molecular weight fraction of fructan was most available for degradation by yeast or by endogenous enzymes present in the ingredients.     

Rapeseed protein concentrate as a potential ingredient for meat analogues

The potential for using rapeseed protein concentrate (RPC) as a novel protein source for meat analogues was investigated using shear cell technology with RPC-only and RPC-wheat gluten (WG) mixtures. The resulting products were characterized by texture analyser, confocal laser scanning microscopy (CLSM) and X-ray microtomography. Soy protein concentrate (SPC) was chosen as the benchmark because of its known capacity to create fibrous structures. Both RPC-only and RPC-WG mixtures could be transformed into fibrous products when processed at 140 °C and 150 °C with 40 wt% dry matter. The fibrous structure was improved by adding of WG into RPC at 140 °C and the colour of the RPC-WG product became lighter with more WG added. CLSM images revealed that the protein formed a continuous phase, and the RPC inherent polysaccharides acted as a dispersed phase. Overall, RPC is concluded as a promising alternative protein source after SPC for meat analogue applications.Industrial relevanceRapeseed meal, which is a by-product from extraction of rapeseed oil, is currently mainly used as animal feed and seldom applied as a food ingredient. This study provides valuable insights into the potential of rapeseed protein concentrate produced by washing rapeseed meal with aqueous ethanol as an alternative plant protein for meat analogues. The outcomes of this study demonstrated the potential of rapeseed protein concentrates for structuring purposes, which is a step towards its commercial use as an environmentally sustainable meat analogue ingredient.     

Orange fibre as potential functional ingredient for dry-cured sausages

Dry-cured sausages with orange fibre (juice industry by-products) at five concentrations (0, 5, 10, 15 and 20 g/kg) were prepared and studied. Chemical (residual nitrite level and lipid oxidation) and physico-chemical parameters (colour and pH) were determined during dry-curing stage (4 weeks). Polyphenol composition (extracted with methanol and separated and quantified by HPLC) of each formulation and its evolution during dry-curing were also determined. TBARS values increased in all samples during drying, with lower increase in treatment samples than in control samples. The incorporation of orange fibre into sausages produced a significant decrease in residual nitrite level. The high reactivity of nitrites could allow its reaction with active biocompounds (polyphenols) present in orange fibre. Chromatographic (HPLC) analysis of orange fibre detected numerous peaks, most of them matched with phenolic compounds. The highest peak of this chromatogram was identified as hesperidin. So, hesperidin was selected as the most adequate compound to monitor polyphenols changes in sausages added with orange fibre during processing.     

叶黄素的生物学作用及制剂研究进展

目的：为提升淀粉在载药领域的应用,旨在制备出纳米级疏水改性淀粉,研究其对疏水性药物的负载效果。方法：以木薯淀粉为原料,采用沉降法制备了纳米淀粉（Nanometer Starch,SNPs）,并以脂肪酶为催化剂,在两相体系对SNPs催化改性,合成了不同取代度（Degree of Substitution,DS）的松香酯纳米淀粉（Rosin Ester Nanometer Starch,RENPS）,考察了SNPs和RENPS在不同条件下对叶黄素的吸附效果。结果：酯化改性未对SNPs形貌产生显著影响,SNPs尺寸分布在250～800 nm,主峰为480 nm,RENPS尺寸分布在100～800 nm,DS的增加,使主峰向左移动;DS与RENPS的疏水性呈现正相关,RENPS的接触角可达93.32°±1.15°,SNPs的接触角仅为51.69°±2.15°。随着DS的增加,RENPS对叶黄素吸附达到平衡的时间逐渐减小,但吸附量逐渐增加。SNPs对叶黄素吸附为一级动力学,RENPS对叶黄素吸附为二级动力学。结论：本研究确定了RENPS的一种疏水改性方法,并且改性后的RENPS对疏水性药物的负载能力得到显著提升。     

Characterisation of alkaline and enzymatic modified insoluble dietary fibre from Undaria pinnatifida

Undaria pinnatifida insoluble dietary fibre (UIDF) was modified by alkali (NaOH solution) and complex enzyme (xylanase and cellulase) to improve the physicochemical properties. Scanning electron microscopy revealed that the surface structure after modification was rough and loose. The characteristic absorption peaks in Fourier transfer infrared spectrometry and X-ray diffraction patterns showed that enzymes can further hydrolyse the UIDF than alkali mainly in amorphous region, and increased the soluble dietary fibre content to 16.31%. The alkaline and complex enzymatic modification both resulted in higher water retention capacity, water swelling capacity, oil absorption capacity, glucose adsorption capacity and the inhibition ability towards α-amylase. The complex enzymatic modification exhibited better features in almost all properties, and the modification did not change the inhibiting mechanism on α-amylase (non-competitive type). Overall, both two modifications could effectively improve the properties of UIDF, which may promote its use in food applications.     

Characterisation of reused osmotic solution as ingredient in new product formulation

Osmotic dehydration (OD) with sugar solutions has been used in fruit preservation but part of the process's economic viability depends on the possibility of reusing the osmotic solution (OS) in successive dehydration cycles. Despite the increase in water content, OD promotes OS enrichment in certain water-soluble natural components extracted from fruits, such as vitamins and minerals. For this reason, to recycle it for new food formulation seems to be an attractive alternative. In this paper, changes in soluble solids, a_w, pH, electrical conductivity, density, viscosity and colour in osmotic solution used for kiwifruit dehydration in function of the ratio osmotic solution/fruit (20:1, 10:1 and 5:1) and the number of cycles (up to 10) have been studied. Microbiological analysis of OS and fruit compositional changes were also studied. The results show that during OD likewise water interchange between fruit and OS, a flow of mineral salts and sugar from the fruit to the OS, is produced. Nevertheless OS changes associated to the OD of kiwifruit under the conditions of this study allow OS reuse for at least 10 cycles without any problems related to fruit dehydration level, colour fruit changes, or considerable microbiological contamination.     

Food product models developed to evaluate starch as a food ingredient

Three highly reproducible food models have been developed to evaluate rheological and functional properties of starches. The food models are dutch vla, dressing, and white sauce, and they vary in pH, serving temperature, oil content, and content of other functional ingredients than starch (milk proteins, whole egg, carrageenan). The viscous properties were calculated in a controlled stress rheometer, and the power law index, n, and the consistency index, K, was calculated. The viscoelastic properties at small deformations were measured by oscillating viscometry. Also a spreadability analysis was performed. The rheological data for the three food models were analysed by use of a principal component analysis (PCA), which enabled an evaluation of the functionality of the models and visualisation of the correlation to the concentration of starch. The rheological parameters all varied significantly with starch concentration in dutch vla. In dressing and white sauce most of the rheological parameters depended on the starch concentration. In addition, it was found that results from the empirical rheological method (USDA consistometer) correlate well with fundamental rheological parameters. Syneresis was measured for a period of time up to 15 days. The degree of syneresis of dressing was highly dependent on starch concentration, while the syneresis of the white sauce was dependent on time but not on starch concentration. The dutch vla showed no syneresis at all.     

Prebiotic effects of cassava fibre as an ingredient in cracker-like products

Cassava fibre, a waste product formed in starch production, was incorporated into wheat to give composite flours at ratios of 80/20, 70/30, 60/40 and 50/50, respectively. A cracker-like biscuit was produced from the preferred ratios (60/40 and 50/50). The effects of these on diets as a prebiotic were evaluated in a rat assay. Determinations of the proximate composition and haematological parameters were made as well as microbiological analysis. The protein content of the cracker-like product based on the 50/50 and 60/40 (fibre/wheat flour) ratios were 15.0% and 10.0%, respectively. Crude fibre ranged from 14.1-17.1% while ash ranged from 3.0 and 5.0%. Low cholesterol levels of 28.75 mg dL(-1) and 18.75 mg dL(-1) were recorded for the 50/50 and 60/40 composite ratios, respectively. The result of liver function test showed that the rats that were fed the fibre-based cracker product had an average value of 44.00 IU L(-1) of aspartate amino transferase (AST), which is lower than the 67.75 IU L(-1) recorded for the control. There was a significant increase in the packed cell volume (PCV) of the rats fed a fibre-based diet, relative to those fed "Ogi" (fermented maize). Haemoglobin was significantly higher in the control sample than all others, while no significant difference was observed in the white blood cell (WBC) count, with average of 11.75 mm(3). Data obtained from the faecal analysis showed that the rats fed with the composite ratios and other diets had an increased Lactobacillus count. However, by increasing the number of days that the rats were fed the fibre-based diet, the E. coli count in the rat faeces reduced significantly. The data obtained shows that cassava fibre-based crackers have good nutraceutic effects, with reduction in the E. coli count found in the rat faeces and healthy performances in terms of weight gain.     

健康食品配料——低聚异麦芽糖

低聚异麦芽糖又称分歧低聚糖,以淀粉为原料采用酶工程技术生产,是功能性低聚糖中产量最大、应用最广泛的一种健康食品配料。低聚异麦芽糖于80年代在日本成功开发,1990年产量达8,000吨,1995年产量为11,000吨,至1997年已达15,000多吨。由于低聚异麦芽糖具有显著的生理功效,且价格极具市场竞争力,发展速度较快,年平均增长率超过10％。     

Analysis of co-crystallized free phytosterols with triacylglycerols as a functional food ingredient

This research focuses on the analysis of mixtures of free phytosterols (FPSs) with fully hydrogenated soybean oil (FHSO):soybean oil (SO) mixtures as a potential zero-trans substitute for various types of shortenings. Oil binding capacity as well as the thermal, rheological and structural properties of FHSO:SO blends containing 0, 20 and 25 wt.% β-sitosterol or stigmasterol were investigated in this study. Differential interference contrast (DIC) microscopy and wide angle X-ray diffraction (WAXRD) revealed that co-crystallization of FPSs with FHSO:SO blends occurred. Polymorphic forms were characterized as a mixture of β′ and β for all samples. The addition of FPSs decreased oil loss (OL) of FHSO:SO samples. Melting profiles of the prepared FPS–TAG (triacylglycerol) blends were extended to higher temperatures compared to a commercial shortening. Rheological properties were comparable to those of commercial puff pastry shortening suggesting that FPS–TAG blends may be acceptable for bakery applications. FPSs co-crystallized with FHSO and SO may be a suitable trans-fat free substitute for a number of types of shortening, including puff pastry shortening. The manufacturing of co-crystallized /FPS-TAG matrices will possibly bring large economic benefits as their functionalization can potentially be achieved by using existing simple shear processing.     

Nutritional characterization of tomato fiber as a useful ingredient for food industry

Tomato by-product consists of peels and seeds, presenting peel high fiber content. In this work, “tomato fiber” (TF) samples, obtained from tomato peels (after tomato processing) by a patented process, were characterized in terms of fiber and macronutrients (proteins, ash, total available carbohydrates and soluble sugars). From our results, TF is mainly composed by carbohydrates, with an average value of 80% of total dietary fiber (much higher than other vegetable by-products), being insoluble fiber the major component. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population.Industrial RelevanceThe use of tomato by-product reduces costs and justifies new investments in equipment, providing a correct solution for the pollution problem connected with tomato processing. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population. According to the Regulation 1924/2006, the product TF characterized in this study can be considered under the denomination of “Source of Fiber” (more than 3 g/100 g), and for that reason food products containing the above mentioned fiber in quantities equal or superior to 3.9%, could also include the same declaration of nutritional properties in their labeling.     

魔芋低聚糖作为新食品原料的应用研究

魔芋多糖是魔芋的主要成分,魔芋低聚糖是魔芋多糖经过酶、酸、辐照等多种方法降解得到的寡糖。魔芋低聚糖作为新食品原料在食品及保健食品中有着广阔的应用前景。与魔芋多糖相比,魔芋低聚糖具有优良的性能,可用于改善食品品质,保鲜食品,同时也适用于多种低脂食品的加工和制作,满足各类人群的需求,有利于人体健康。另外,魔芋低聚糖作为功能因子,对机体有多方面的保健功效,有望用于保健食品行业,来改善人体肠道菌群,增强免疫力,调节血糖、血脂等。总之,魔芋低聚糖是一种理想的食品原料或者食品添加剂。本文从魔芋低聚糖的制备,在食品及保健食品中的应用等方面对魔芋低聚糖进行了综述。     

Impact of processing on the functionalization of pumpkin pomace as a food texturizing ingredient

In the context of side-stream valorization, this study aimed to gain insight into the functionalization of industrially-generated pumpkin pomace as texturizing ingredient. Given the matrix complexity of pumpkin pomace, composed of crushed peels, seeds and mesocarp, this study focused on the impact of different sample preparation, as well as mechanical processing, on the microstructural and rheological properties of pumpkin pomace suspensions. Pumpkin pomace suspensions (4% w/w) possessed a solid-like behavior, demonstrating the potential for structure build-up. The application of heat during sample preparation (85°C, 30 min) significantly increased the storage modulus of the pumpkin pomace-derived suspensions, which was found to be related to an increased swelling volume of the suspended particles. Moreover, a combination of partial pectin removal and high pressure homogenization at 80 MPa led to improved network structure formation, as obvious from an increased storage modulus. These results are highly useful as scientific basis for exploring the texturizing potential of pumpkin pomace with minimal processing or conventional preparation methods (e.g. by heat treatment).     

Species identification by SDS-PAGE of red algae used as seafood or a food ingredient

The identification, by SDS-PAGE, of four red algae used as sea vegetables or ingredients by the food industry, was performed. They were Palmaria palmata (Dulse), Chondrus crispus (Pioca), Porphyra umbilicalis (Nori), Gracilaria verrucosa (Ogo-nori). For each species, variations in protein patterns were observed, according to the season. However, for all species, some protein bands were always present during the yearly cycle of the plant. The reference pattern of P. palmata was composed of six protein bands with apparent molecular weights between 59.6 and 15.2 kDa. The G. verrucosa pattern was constituted of eight permanent bands. Two pattern bands, with apparent molecular weights of 49.1 and 45.9 kDa,differentiated the G. verrucosa profile from other seaweed patterns. C. crispus could be identified by a reference pattern composed of seven bands; three, with close molecular weights (49.3; 46.2 and 43.2 kDa), were characteristic of this species. Finally, the P. umbilicalis pattern showed seven bands with molecular weights between 73.1 and 15.9 kDa. The presence of a band with a molecular weight above 70 kDa appeared to be specific to the Porphyra pattern. So the SDS-PAGE seemed able to identify the four red species used by the food industry, but this analytical method appeared to be applicable only to raw material dried in mild conditions.