Technologies for enhancement of bioactive components and potential health benefits of cereal and cereal-based foods: Research advances and application challenges

Cereal grains are a major source of human food and their production has steadily been increased during the last several decades to meet the demand of our increasing world population. The modernized society and the expansion of the cereal food industry created a need for highly efficient processing technologies, especially flour production. Earlier scientific research efforts have led to the invention of the modern steel roller mill, and the refined flour of wheat has become a basic component in most of cereal-based foods such as breads and pastries because of the unique functionality of wheat protein. On the other hand, epidemiological studies have found that consumption of whole cereal grains was health beneficial. The health benefit of whole cereal grain is attributed to the combined effects of micronutrients, phytochemicals, and dietary fibre, which are mainly located in the outer bran layer and the germ. However, the removal of bran and germ from cereal grains during polishing and milling results in refined flour and food products with lower bioactive compounds and dietary fibre contents than those from whole grain. Also, the level of bioactive compounds in cereal food is influenced by other food preparation procedures such as baking, cooking, extrusion, and puffing. Therefore, food scientists and nutritionists are searching for strategies and processing technologies to enhance the content and bioavailability of nutrients, bioactive compounds, and dietary fibre of cereal foods. The objective of this article was to review the research advances on technologies for the enhancement of bioactive compounds and dietary fibre contents of cereal and cereal-based foods. Bioactivities or biological effects of enhanced cereal and cereal-based foods are presented. Challenges facing the application of the proposed technologies in the food industry are also discussed.     

Effect of chlorophyll removal and particle size upon the nutritional and technological properties of powdered by‐products from artichoke (Cynara scolymus,L.) industrial canning

In this study, the effect of the particle‐size fractionation (Ø < 0.212 mm and 0.212 mm < Ø < 0.991 mm) and chlorophyll extraction on the nutritional and technological properties of the powdered artichoke ingredient was evaluated. The contents of minerals, protein, fat, carbohydrates and dietary fibre together with the content in bioactive compounds such as inulin and phenolics were determined. Other properties such as water‐ and oil‐holding capacities, water activity and antioxidant capacity were measured. The ingredient with chlorophyll and the lowest particle size presented the highest phenolic content and antioxidant capacity (8.4 mg of vitamin C equivalents per 100 g of dry matter) and water‐ and oil‐holding capacities. The removal of chlorophyll increased the oil‐holding capacity (from 59.7% to 94.6%), which was much higher than in the coarse ingredient (34%), but has a deleterious effect reducing the antioxidant capacity and the inulin content. The ingredients also showed high dietary fibre (22.5–33%), inulin (9–16%) and mineral (7.5–7.8%) contents. Although the ingredient with chlorophyll and smaller particle size had the higher antioxidant capacity, the removal of chlorophyll improved the technological properties to be used as food ingredient without affecting significantly to the nutritional value.     

Roselle (<Emphasis Type="Italic">Hibiscus sabdariffa</Emphasis>) by-product as functional ingredient: effect of thermal processing and particle size reduction on bioactive constituents and functional,morphological, and structural properties

Food industry is in the search of new functional ingredients, so this study was focused on evaluating the effect of thermal processing used to produce roselle beverages, and the effect of particle size reduction, on the retention of bioactive constituents, and physicochemical, functional, and structural properties of Hibiscus sabdariffa calyces. After decoction process (DP), by-products retained up to 56% of polyphenolic compounds, 54% of flavonoids and 44% of anthocyanins; mainly delphinidin 3,5-O-diglucoside (74.1%); besides presenting an increased content of total dietary fiber (DF) as compared to roselle calyces (26%). Viscosity and hydration properties were improved by the DP, which may be related to an increased porosity as observed in the SEM micrographs. Fourier transform infrared spectroscopy spectrum, reflected the differences in the chemical composition of BP and calyx, whereas the X-ray diffraction analysis showed no effect of DP. Interestingly, samples with a large particle size (250–177 µm) presented increased viscosity, which was the most important change for particle size. Therefore, roselle beverage by-product could be a functional ingredient since is an excellent source of phenolic compounds and dietary fiber with improved functional and physicochemical properties as compared to calyces.     

Effects of Brewer's Spent Grain on the Quality and Dietary Fibre Content of Cookies

Dried and ground brewer's spent grain (BSG) was blended with soft wheat flour at levels of 5–25%. BSG preparations of fine (<212 μm), medium (212–425 μm) and coarse (425–850 μM) particle sizes were used in the production of wire‐cut cookies. The protein content decreased and the dietary fibre content (acid detergent fibre, neutral detergent fibre and total dietary fibre) increased, as the particle size of the BSG samples increased. The results indicated that BSG preparations with high dietary fibre content have potential as a source of dietary fibre. The effects of BSG on the quality and dietary fibre content of cookies have been investigated. Total dietary fibre (TDF) contents of the cookies supplemented with different particle size BSG increased significantly (p<0.05) as the addition level increased. Cookies prepared with BSG of medium and coarse particle sizes resulted in better properties in terms of Spread Ratio, Hunter color values and overall sensory score as compared to those made with BSG of fine particle size. Cookies made with medium and coarse particle size BSG gave better cookie properties up to the 15% addition and deteriorated significantly above this level (p<0.05).     

Chemical profile, functional and antioxidant properties of tomato peel fiber

Tomato processing residue is defined as a secondary raw material that can increase its value, being considered a potential source of dietary fiber and bioactive compounds. Commercial tomato peel fiber has been analyzed to ascertain the proximate and nutritional composition (moisture, fat, protein, dietary fiber, ash, and minerals), the fractions (insoluble, IDF, and soluble, and SDF) and sugar composition of dietary fiber, functional properties (water retention capacity, WRC, swelling capacity, SWC, fat absorption capacity, FAC, glucose diffusion retardation index, GDRI, and osmotic pressure), total antioxidant activity (AA), and the content of antioxidant bioactive compounds (phenolic compounds and lycopene). To extract phenolic compounds and dietary fiber, three methods were assayed in this study: enzyme hydrolysis, maceration, and ultrasonic assistance. The content of TDF was 84.16%, and the major fraction was the IDF (71.82%), formed mainly by hemicelluloses. Tomato peel fiber retained 6.76 g of water/g as WRC, and it was significantly correlated with the IDF content. In addition, the content of IDF determined the low FAC and SWC and the GDRI at 60 min (39.22%). The main phenolic compound was rutin, followed by naringenin, rutin derivatives, and chlorogenic acid derivatives. These were better extracted using ultrasonic assistance, whereas lycopene showed mean values between 3 and 4 mg/100 g. The AA of tomato peel fiber was low, since the phenolic compounds are mainly bound to the cell wall of plant, showing a low capacity for scavenging radicals. Due to its chemical profile and functional properties, tomato peel fiber can be used as a food supplement, improving the different physical, chemical, and nutritional properties of foods. However the color and flavor of this product must be considered in its applications to avoid a negative effect on the sensory characteristic of the foods to which it is added.     

Mango peel fibres with antioxidant activity

 Antioxidant compounds associated with some types of dietary fibres may be responsible in part for the beneficial effects on health of high-dietary-fibre diets. The antioxidant activity of a high-dietary-fibre mango peel product and of some commercial samples was determined by the ferric thiocyanate colorimetric method. At a concentration of 0.05%, the antioxidant activity of mango peel dietary fibre was 0.75 times as effective as that of 2-tert-butyl-4-hydroxyanisol (BHA) and 1.4 and 3.4 times higher, respectively, than that of French PARAD’OX (a commercial polyphenols concentrate) and of DL-α-tocopherol. All Bran, Quaker Oats, lemon and apple fibre did not exhibit any antioxidant capacity. The obtention of high-dietary-fibre products with bioactive compounds could be useful for the food industry and the antioxidant activity may be a new property to consider in the quality evaluation of these ingredients. Received: 25 January 1996 / Revised version: 10 June 1996     

Mango peel fibres with antioxidant activity

 Antioxidant compounds associated with some types of dietary fibres may be responsible in part for the beneficial effects on health of high-dietary-fibre diets. The antioxidant activity of a high-dietary-fibre mango peel product and of some commercial samples was determined by the ferric thiocyanate colorimetric method. At a concentration of 0.05%, the antioxidant activity of mango peel dietary fibre was 0.75 times as effective as that of 2-tert-butyl-4-hydroxyanisol (BHA) and 1.4 and 3.4 times higher, respectively, than that of French PARAD’OX (a commercial polyphenols concentrate) and of DL-α-tocopherol. All Bran, Quaker Oats, lemon and apple fibre did not exhibit any antioxidant capacity. The obtention of high-dietary-fibre products with bioactive compounds could be useful for the food industry and the antioxidant activity may be a new property to consider in the quality evaluation of these ingredients. Received: 25 January 1996 / Revised version: 10 June 1996     

Preparation of β-glucan and antioxidant-rich fractions by stone milling of hull-less barley

Stone milling of hull-less barley in combination with size-based separation of the milled fractions was used for preparation of flours with different compositions of macronutrients and bioactive compounds. According to similar compositions, specific milled fractions were combined to define three flours. The flour with the largest mass fraction (~70%) comprised particle sizes < 124 μm, which showed lower fibre, residual ash and antioxidant contents than the unfractionated flour. The flour with particles from 124 to 250 μm (~20% mass fraction) had >twofold greater β-glucan content, and the flour with particles > 250 μm (~10% mass fraction) had >threefold greater content of antioxidants than unfractionated flour. Each of these three flour fractions represents valuable material that can be incorporated into bakery products to enhance functional and health-related properties. Large enrichment factors of bioactive compounds in barley flours can be obtained using small-scale and widely available milling equipment.     

Feasibility of use of buckwheat flour as an ingredient in ginger nut biscuit formulation

Ginger nut biscuits are popular traditional biscuits which contain honey. In order to improve their nutritive profile and functionality, standard formulation based on wheat flour was substituted with buckwheat flour at three levels (30%, 40%, 50%). The quality attributes (chemical composition, microelements, bioactive compounds (total polyphenols, rutin, quercetin), antioxidative potential, textural and sensory properties) were compared to control biscuit (based on wheat flour) and biscuits substituted with rye at the same levels, since rye is used as an ingredient which improves the quality of ginger nut biscuits. Substitution with buckwheat flour resulted in a significant increase (p < 0.05) in protein, Zn, total polyphenols, antioxidative and chelating activity. Total dietary fibre, Cu, Mn and Fe contents also increased but did not exceed those in rye substituted biscuits. Consumption of 100 g of enriched biscuits could contribute to reaching ≈18–22% (buckwheat) and 16–17% (rye) of the estimated daily average total polyphenols intake, respectively. With the contents of rutin and quercetin at 3.96–6.57 mg/100 g d.b. and 0.087–0.214 mg/100 g d.b., respectively, buckwheat substituted biscuits may significantly contribute to total dietary flavonoid intake and meet the demands of preventive nutrition. Buckwheat enriched biscuits were rated higher regarding sensory attributes, softness and fracturability as compared to control but lower compared to rye supplemented biscuits.     

Dietary fibre: The scientific search for an ideal definition and methodology of analysis,and its physiological importance as a carrier of bioactive compounds

There is a growing need for a global consensus on the definition of dietary fibre and the use of appropriate methodologies for its determination in different food matrices. Oligosaccharides (prebiotic effect) and bioactive compounds (antioxidant effect) are important constituents of dietary fibre, which enhance its beneficial effects in the body, such as those related to maintaining intestinal health. These dietary components need to be quantified and addressed in conjunction with fibre in nutritional studies due to the close relationship between them and their common destiny in the human body. This review discusses updates to the concept of dietary fibre, with an emphasis on biological and methodological aspects, and highlights the physiological importance of fibre as a carrier of bioactive compounds.     

Influence of Particle Size Reduction on Structural and Mechanical Properties of Extruded Rye Bran

Rye bran is a high-fibre ingredient also containing starch and protein. The aim of this work was to investigate the effects of extrusion processing and bran particle size on the structural and mechanical properties of extruded rye bran. Native rye bran particle size of 750–1,250 μm was milled to produce feed material with three different average particle sizes (coarse, 440 μm; medium, 143 μm; fine, 28 μm). A co-rotating twin screw extruder was used for extrusion with various processing parameters. Extrusion processing did not have a significant (P?<?0.05) effect on soluble dietary fibre (SDF) content but the amount of insoluble dietary fibre (IDF) increased by 7.1–9.5 % in medium- and 11.3–12.3 % in fine-particle-sized rye bran extrudates as compared to the raw material prior to extrusion. Decreasing the particle size of rye bran to 28 μm resulted in lower amounts of IDF and total dietary fibre, but a higher amount of SDF after extrusion compared to coarse-particle-sized rye bran. Decreasing the particle size of rye bran to 28 μm gave more expanded (179–223 %), less hard (145–336 N), more crispy (2.7–7.2?×?10^?4) and porous (79.2–83.9 %) extrudates compared to the coarse-particle-sized rye bran extrudates, which were less expanded (151–176 %), harder (210–433 N), less crispy (0.5–2.8?×?10^?4) and less porous (64.4–65.1 %). Reduction of the particle size of rye bran significantly (P?<?0.05) increased the crispiness compared to the extrudates made of coarse-particle-sized rye bran. The results demonstrated that the structural and mechanical properties of rye bran extrudates can be improved without starch addition by reducing the particle size of bran.     

Effect of particle size on flow behaviour and physical properties of semi-ripe plantain (AAB Musa spp) powders

This work was conducted to study the influence of particle size and shape on the flow behaviour of semi-ripe plantain powders. An improved plantain variety (Big Ebanga), two hybrids (FHIA 21 and PITA 3), and a local variety (Corne 1, as reference material) were powdered by successive drying, milling, and sieving into three granulometric classes: unsieved (<500 µm), fine fraction (<180 µm; class 1), and coarse fraction (between 180 and 500 µm; class 2), thus differing in particle size distribution. Physical properties (water activity, particle size distribution, shape factors) were characterised and flow properties (basic flowability energy, compressibility, fluidisability, cohesion, etc.) were investigated using the FT4 powder rheometer. Convexity of unsieved and fine powders was slightly higher than for coarse powders. Fine powders of all plantain varieties were found to have the lowest water activity and the lowest flowability in unconfined conditions. Unsieved and fine powders presented a fluidised state at the end of the FT4 standard aeration test and their minimum fluidisation velocity was low, confirming the good fluidisability of these powders.     

Effect of micronised oat bran by ultrafine grinding on dietary fibre,texture and rheological characteristic of soft cheese

The purpose of this research was to study the effect of micronised oat bran on dietary fibre, textural and rheological of soft cheese. The soft cheese was processed by using the different particle size oat bran as fibre supplement, and its dietary fibre content, rheological and textural properties were determined. The results show that the micronised oat bran with 5–30 μm particle size was prepared by ultrafine grinding and passed through 60–400 mesh sieves. The soluble dietary fibre content in micronised oat bran soft cheeses was higher than that of the control (untreated oat bran soft cheeses; P < 0.05), with a maximum of 2.65 g per 100 g cheeses when oat bran was ultrafine crushed and passed through 300 mesh sieves, while the content of insoluble dietary fibre was lower than that of the control (P < 0.05). The micronised oat bran soft cheese in fermentation is a typical non-newtonian fluid. G′, G″ and apparent viscosity of soft cheeses were increased with the reduction of oat bran particle size. The chewiness and springiness of micronised soft cheeses were increased with the reduction of oat bran particle size, and were higher than that of the control (P < 0.05). The hardness and cohesiveness of micronised soft cheese were decreased with the reduction of oat bran particle size, the hardness was lower, but the cohesiveness of micronised soft cheese was higher than that of the control (P < 0.05). The 1% micronised oat bran can obtain better processing characteristics and overall acceptability for cheese products.     

Effects of enzymatic/alkali protein removal and particle size reduction on physicochemical and functional characteristics of okara dietary fibre

The combined effects of enzymatic/alkali protein removal treatments and superfine grinding on the characteristics of okara dietary fibre (DF) were investigated. Protein removal could effectively increase the obtained DF content and further enhance water-holding capacity (WHC), swelling capacity (SC) and oil-holding capacity (OHC). The DF with Alcalase treatment and superfine grind through 500-μm mesh size had the highest total dietary fibre, WHC (12.5 g g⁻¹), SC (12.7 mL g⁻¹) and OHC (2.7 g g⁻¹). Decreasing particle size will trigger a redistribution of some fibre composition from the insoluble to the soluble fraction. The WHC and SC of the sieved DFs decreased with reducing mesh size (500–40 µm). The OHC of DF with Flavourzyme treatment reduced with decreasing mesh size (500–100 µm), but improved with mesh size less than 100 µm.     

Improved function of bamboo shoot fibre by high-speed shear dispersing combined with enzyme treatment

With the increase in global welfare, metabolic syndrome-related diseases seriously disrupt our quality of life. Balanced diet with low calories, low glycaemic index, and high dietary fibre such as bamboo shoot fibre is needed. Functional properties of dietary fibre can be improved by processing methods. Therefore, we compared the effect of three processing methods (high-speed shear dispersing, enzyme treatment and combined treatment) on the characteristics and functions of bamboo shoot fibres. Combined treatment resulted in high SDF content (10.15%), adsorption capacity of glucose (4.45–18.18 mmol g⁻¹), nitrite ion (505.49 μg g⁻¹ [pH 2.0]), and cholesterol (333.72 μg g⁻¹ [pH 2.0]). FTIR revealed that hydroxyl groups, sugar methylene and benzene rings of aromatic compounds existed in the treated bamboo shoots. The particle size (D₅₀) decreased from 383.90 to 30.65 μm. Honeycomb-like structure was also observed through SEM. Thus, proper processing of bamboo shoot fibres can improve their functions as food ingredients.     

Effects of particle size reduction of insoluble fibres by micron technology on various caecal and faecal indices

BACKGROUND: Previous findings demonstrated that particle size reduction of insoluble fibre materials (i.e. starfruit insoluble fibre‐rich fraction and cellulose) to micro‐sizes effectively enhanced their physicochemical properties, which provided clues to their physiological functions. The aim of the present study was to investigate the effects of particle size reduction of these insoluble fibres by micron technology on indices of bowel health. RESULTS: Feeding of the micronised fibres (9.68–14.3 µm), especially those prepared by high‐pressure micronisation, effectively (P < 0.05) improved various caecal and faecal indices, such as decreasing the caecal ammonia concentration (by 20.0–30.0%), increasing the faecal output (135–150%) and moisture content (143–157%) and lowering the activities of undesired β‐D ‐glucosidase (by 39.2–43.6%) and β‐D ‐glucuronidase (by 71.4–77.5%) in faeces of hamsters. Relationships between physicochemical properties and physiological functions of the micronised fibres were considered. The results also demonstrated that the type, processing and related particle size of insoluble fibres were important factors affecting their physicochemical properties and physiological functions. CONCLUSION: The consumption of micronised insoluble fibres at 5% level might exert a favourable effect on improving various caecal and faecal indices. The results of this study provide some hints on potential applications of micron technology in the food industry. Copyright © 2007 Society of Chemical Industry     

Bioactive components,physicochemical and starch characteristics of different parts of lotus (Nelumbo nucifera Gaertn.) plant: a review

Lotus plant parts such as flower, seed, root, leaf and stem or rhizome have a great potential for food and non-food applications. This review recognises the nutritional and therapeutic benefits, functional behaviour, post-harvest processing and applications of the lotus plant. Its unique bioactive constituents, such as phenolic compounds, alkaloids, flavonoids and essential oils, have proven efficacy in improvement of health. The good amount of dietary fibre, starch, vitamins and minerals suggest that it has potentially an appropriate opportunity for future valorisation and application as functional additive and ingredient in the food industry. As a functional ingredient for use in the food industry like flour in bakery industry, as an antioxidant, for incorporation in baby foods, extruded products, beverages etc. there is a need to study the characteristics of lotus plant especially the rhizome part.     

Effect of tiger nut fibre addition on the quality and safety of a dry-cured pork sausage (“Chorizo”) during the dry-curing process

There is a growing interest in the revalorization of co-products from the food industry. Co-products from tiger nuts (Cyperus esculentus) milk production are a suitable fibre source. “Chorizo” is the most popular dry-cured meat product in Spain. The aim of this work was to study the effect of the tiger nut fibre addition (0, 5, and 7.5%) on the quality (composition, physicochemical, and sensorial properties) and safety (oxidation and microbial quality) of a Spanish dry-cured sausage, during the 28 days of its dry-curing process. Tiger nut fibre (TNF) addition decreased fat and increased moisture content. The addition of TNF significantly increased (p < 0.05) the total dietary fibre content of “Chorizo”. Lightness (L*), yellowness (b*) and redness index (a*/b*) were significantly (p < 0.05) affected by the fibre content. The addition of 5% and 7.5% TNF to chorizo provided rich fibre and a healthier product. Although there were slight changes in the physicochemical properties, its quality (traditional characteristics) and its safety remained.     

水溶性膳食纤维Fibersol-2

由于人们对膳食纤维与人体机能关系的认识不断深入，膳食纤维的重要性被世界所承认。在许多国家除了糖、蛋白质、脂肪、维他命、矿物质之外，膳食纤维被称为第六营养素。但是，随着许多结构的变化，生活节奏的加快，饮食习惯和食物构成的改变，现代人的饮食生活出现膳食纤维不足现象。[Fibersol-2]不仅是水溶性食物纤维的纤维源，而且具有各种各样的生理机能，能满足人们的健康需要，对形形色色健康食品的开发有关极其广泛的应用前景。