Date flesh: Chemical composition and characteristics of the dietary fibre

The date by-products of two date palm (Phoenix dactylifera L.) cultivars, Deglet-Nour and Allig, from the Degach region (Tunisia), were analysed for their main chemical composition. Studies were also conducted on the physicochemical properties (colour, water and oil-holding capacity and rheological behaviour) of dietary fibre (DF) extracted from date flesh. The following values (on a dry matter basis: DM) were obtained for fleshes of Deglet-Nour and Allig cultivars, respectively: sucrose 52.7% and 13.9%, glucose 13.7% and 29.9%, fructose 12.6% and 29.0%, total dietary fibre 14.4% and 18.4%, protein 2.1% and 3%, ash 2.5% and 2.52%. Insoluble DF, the major fraction of total DF, constituted 9.19–11.7% DM for Deglet-Nour and Allig, respectively. The elaboration of DF concentrates from date fleshes was characterised by an extraction yield of 67%. The chemical composition of these DF concentrates showed high total DF contents (between 88% and 92.4% DM) and low protein and ash contents (8.98–9.12% and 2.0–2.1% DM, respectively). The DF concentrates showed a high water-holding capacity (∼15.5 g water/g sample) and oil-holding capacity (∼9.7 g oil/g sample) and pseudoplasticity behaviour of their suspensions. Thus, date DF concentrates may not only be an excellent source of DF but an ingredient for the food industry.     

Effect of extraction method on chemical composition and functional characteristics of high dietary fibre powders obtained from asparagus by-products

Asparagus (Asparagus officinalis L.) by-products, which represent around 50% of the processed vegetable, are a potential source of dietary fibre. The way that these by-products are treated affects the composition and functional properties of fibre-rich powders. Factors such as treatment intensity, solvent, and drying system were studied. Only the more soluble components (soluble sugars, uronic acids and proteins) showed significant differences. All the fibre-rich powders had high concentrations of TDF (62–77%). The IF/SF proportion decreased with the severity of treatment, in this way increasing the physiological quality of the fibre. Functional properties, namely water-holding capacity (WHC), oil-holding capacity (OHC), solubility (SOL), and glucose dialysis retardation index (GDRI), varied according to the preparation procedure. WHC and GDRI were higher in intensely extracted fibres; due to the effect of thermal processing. WHC showed values (11–20 ml water/g powder) similar to those described for other agricultural by-products, but OHC and GDRI were much higher (5–8 ml oil/g powder and 25–45%, respectively). These properties make fibre-rich powders from asparagus by-products a valuable source of dietary fibre to be included in the formulation of fibre-enriched foods.     

Antioxidant capacity of the Spanish Mediterranean diet

The objective of this work was to determine the total dietary antioxidant capacity (TDAC) of the Spanish Mediterranean diet. The antioxidant capacity of plant foods and beverages included in National food consumption data was determined. TDAC of the Spanish diet was estimated at 6014 and 3549 μmol trolox equivalents by FRAP (ferric reducing antioxidant power) and ABTS (free radical-scavenging capacity) procedures, respectively. About 68% of TDAC came from beverages and 20% from fruits and vegetables, with a very low contribution from cereals. The capacity to inhibit in vitro LDL oxidation of plant foods and beverages was consistent with their antioxidant capacity. The recommended daily intakes of antioxidant vitamins, C and E, represent about 10% of TDAC. Total phenolics intake was estimated as 1171 mg gallic acid/person/day by the Folin–Ciocalteau method. TDAC may be a parameter to be considered in nutritional and epidemiological studies.     

Nutritional value and antioxidant capacity of lunch meals consumed by elderly people of Sharpeville,South Africa

The main objective of this study was to determine the nutritional value and the total dietary antioxidant capacity (TDAC) of lunch meals consumed by elderly people attending a day-care centre in Sharpeville, South Africa. Meals were monitored and collected for a two-week period. The menus were analysed for water, ash, fat, protein, carbohydrates, polyphenols and antioxidant capacity. Eighteen food items, grouped in seven different menus, were identified. Energy provided by the menus covered 32% of the daily reference intakes for females and 25% for males, and the distribution of macronutrients in the menus was 10%, 34% and 56% for protein, fat and carbohydrates, respectively. This is close to the prescribed acceptable macronutrient distribution ranges of 10–35% protein, 20–35% fat and 45–65% carbohydrates. TDAC available from the menus was estimated at 332 μmol Trolox equivalents by DPPH (2,2′-diphenyl-1-picrylhydrazyl) and represented about 9% of the recommended daily allowance. Fruit, which represented only 2.8% of the amount of foods composing the menus, supplied 75.3% of TDAC, whilst contributions from vegetables and legumes were low. With 269 mg gallic acid equivalent in the menus, total phenolics appeared to be quantitatively the main dietary antioxidant, and were significantly correlated (r = 0.443 and p = 0.007) with antioxidant capacity. Fruit portions of the meals served by the day-care centre to the elderly of Sharpeville, need to be increased and diversified in order to reinforce their intake of antioxidants and thus reduce the incidence of non-communicable diseases.     

Nutritional and functional properties of dates: a review

This review article provides information on the nutritional and functional constituents of dates (Phoenix dactylifera L.) and their seeds from over 80 references. Date flesh is found to be low in fat and protein but rich in sugars, mainly fructose and glucose. It is a high source of energy, as 100 g of flesh can provide an average of 314 kcal. Ten minerals were reported, the major being selenium, copper, potassium, and magnesium. The consumption of 100 g of dates can provide over 15% of the recommended daily allowance from these minerals. Vitamins B-complex and C are the major vitamins in dates. High in dietary fiber (8.0 g/100 g), insoluble dietary fiber was the major fraction of dietary fiber in dates. Dates are a good source of antioxidants, mainly carotenoids and phenolics. Date seeds contain higher protein (5.1 g/100 g) and fat (9.0 g/100 g) as compared to the flesh. It is also high in dietary fiber (73.1 g/100 g), phenolics (3942 mg/100 g) and antioxidants (80400 micromol/100 g). This detailed information on nutritional and health promoting components of dates and their seeds will enhance our knowledge and appreciation for the use of dates in our daily diet and their seeds as a functional food ingredient.     

Evaluation of the antioxidant activity of asparagus,broccoli and their juices

Antioxidant activity of asparagus, broccoli and their juices was evaluated using 2,2′-diphenyl-l-picrylhydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and β-carotene bleaching assays. Asparagus showed greater antioxidant activity than broccoli. Asparagus juice also had greater antioxidant activity than broccoli juice. Methanol and acetone extracts of asparagus and broccoli had significantly greater antioxidant activity than their water extracts. Asparagus and broccoli extracts, as well as their juices, showed no significant difference in total phenolics content. However, asparagus contained more flavonoids than broccoli. The antioxidant activity of asparagus and broccoli extracts demonstrated a linear relationship with their flavonoid content.     

Effect of sterilisation on dietary fibre and physicochemical properties of onion by-products

Food industries are forced to develop productions without secondary residues. Therefore, there is a considerable emphasis on the recovery, recycling and upgrading of wastes. The possibility has been suggested for the conversion of onion waste into food ingredients, but with a stabilisation treatment being necessary. The objective of this work was to study the effect of sterilisation on fibre fractions, fibre composition and physicochemical properties of onion by-products to evaluate the use of sterilised onion by-products as a source of fibre.     

Total phenolics, flavonoids and antioxidant activity of tropical fruit pineapple

Pineapple has several beneficial properties including antioxidant activity. The fruit of pineapple was extracted with ethyl acetate, methanol and water. The phenolic content of the extracts was determined by Folin-Ciocalteu method and antioxidant activity was assayed through some in vitro models such as antioxidant capacity by phosphomolybdenum, ??-carotene-linoleate, and radical scavenging activity using ??,??-diphenyl-??-picrylhydrazyl (DPPH) method. The phenolic contents of the extracts as caffeic acid equivalents were found to be highest in methanol (51.1%) followed by ethyl acetate (13.8%) and water extract (2.6%). Antioxidant capacity of the extracts as equivalent to ascorbic acid (??mol/g of the extract) was in the order of methanol extract > ethyl acetate extract > water extract. In comparison with butylated hydroxyanisole (BHA), at 100 ppm of concentration, the antioxidant and free radical scavenging activities of the extracts assayed through ??-carotene-linoleate and DPPH method were also found to be highest with methanol extract followed by ethyl acetate and water extracts. The results indicated that the extent of antioxidant activity of the extract is in accordance with the amount of phenolics present in that extract and the pineapple fruit being rich in phenolics may provide a good source of antioxidant.     

Date syrup: Effect of hydrolytic enzymes (pectinase/cellulase) on physico-chemical characteristics, sensory and functional properties

This work is a contribution to give value addition to second grade dates (with hard texture) by the production of enzymatically treated syrup with high commercial value. It was observed that the pulp:water at ratio 1:3 treated with 50 U of pectinase and 5 U of cellulase during 120 min at 50 °C gave the highest recovery of total soluble solids (72.37 g of total soluble solids/100 g fresh basis) and the lower turbidity (186.45 NTU) compared with control without enzyme addition (Total soluble solids yields: 66.34 g of total soluble solids/100 g fresh basis and turbidity: 1513 NTU). physico-chemical measurements indicated that carbohydrates were predominant in all date varieties as well as their syrups (∼69.59-83.76 g/100 g dry matter in dates and ∼62.14-74.68 g/100 g fresh weight in syrup). Allig variety was characterised by a high content of reducing sugars content (∼77.91 g/100 g dry matter), contrary to Deglet Nour (∼23.17 g/100 g dry matter) and Kentichi (∼21.3 g/100 g dry matter).The CIE L∗ a∗ b∗ colour values of the enzyme-treated date syrup of Deglet Nour, Allig and Kentichi variety showed lighter colours (L∗ values ranging from 24.16 to 44) than the control without enzyme (L∗ values ranging from 0.545 to 17.2). Hedonic evaluation showed that enzyme-treated date syrup was more appreciated by consumers. Microbiological study showed that date syrups were free from aerobes, moulds, coliforms and enterobacteriaceae and were microbiologically stable during five months storage. Results suggested that enzymatic treatment could be used for production of date syrup with high commercial value     

Screening of some Algerian medicinal plants for the phenolic compounds and their antioxidant activity

Since recent times, there is a growing interest in the food industry and in preventive health care for the development and evaluation of natural antioxidants from medicinal plant materials. In the present work we have investigated the antioxidant potency of phenolic compounds of 11 indigenous wild plant species from the Algerian Atlas commonly used in Arab folk medicine for a wide range of conditions. The antioxidant activity of each phenolic extracts has been assessed by using the Trolox Equivalent Antioxidant Capacity (TEAC) as a chemical test, and in a dynamic way by a biological assay based on whole blood resistance to free radical aggression. Of the 11 tested plants, 2 showed prominent antioxidant activity: Anthemis arvensis and Artemisia campestris. These plants had a very high level of Trolox equivalents and induced a strong delay of free radical-induced red blood cells hemolysis compared to antioxidant references. Artemisia campestris was the best inhibitor, its effect was far stronger than that of caffeic acid and was more than three times as high as ascorbic acid and two times higher than α-tocopherol efficiency. HPLC analysis showed a good correlation between the antioxidant activity and hydroxycinnamic derivatives. These preliminary results on the in vitro protection of blood against oxidative stress emphasized the benefit of the phenolic compounds of these medicinal plants. Our results enable us to proceed towards more detailed chemical and pharmacological understanding of these plant materials and show the interest of natural antioxidant in medicinal plants for the prevention of much free radical-mediated pathology.     

Effects of boiling and microwaving treatments on nutritional characteristics and antioxidant activities of Agaricus blazei Murril

The effects of boiling and microwaving on nutritional compositions, antioxidant components and antioxidant activities of fresh and frozen A. blazei Murril (AbM) were evaluated and compared. The results showed that the contents of crude protein, ash, total soluble protein, total soluble sugar, vitamin C, and total phenolics decreased by both cooking treatments, but no significant changes were observed in lipids. Amino acid composition analysis showed that the ratio of total essential amino acids to total amino acids increased, and the ratio of total non‐essential amino acids to total amino acids thus decreased by both cooking treatments. Boiling and microwaving significantly decreased the contents of glucose, galactose and mannose, and the effect of boiling was higher than that of microwaving. Furthermore, boiling and microwaving significantly decreased the DPPH‐scavenging activity and reducing power of AbM. Analysis of the relations between the antioxidant activities and total phenolic concentrations testified that the cooking treatments not only decreased the total phenolic contents, but also changed the types and relative amounts of phenolic compounds of AbM.     

Dietary fibre and fibre-rich by-products of food processing: Characterisation,technological functionality and commercial applications: A review

Incidental products derived from the manufacturing or processing of plant based foods: cereals, fruits, vegetables, as well as algae, are sources of abundant dietary fibre. These fibre-rich by-products can fortify foods, increase their dietary fibre content and result in healthy products, low in calories, cholesterol and fat. They may also serve as functional ingredients to improve physical and structural properties of hydration, oil holding capacity, viscosity, texture, sensory characteristics, and shelf-life. Analytic methods and fractionation techniques of dietary fibres are evaluated.     

Influence of fibre from different cereals on the rheological characteristics of wheat flour dough and on biscuit quality

Demand for health oriented products such as sugar-free, low calorie and high fibre products is increasing. One such recent trend is to increase the fibre content in food products to overcome health problems such as hypertension, diabetes, and colon cancer, among others. Consumption of high fibre products consisting of indigestible cellulose, hemicellulose, lignin and gums have several health benefits. Apart from these benefits, β-glucan-rich fibres have the benefit of reducing the absorption of glucose. Fibre sources from wheat, rice, oat and barley were used to study their influence on rheological characteristics of wheat flour dough and biscuit making quality. Ash, total protein and dietary fibre content of bran samples ranged between 4% and 10%, 12% and 14% and 20.4% and 49.5%, respectively. Farinograph characteristics of the wheat flour-bran blends showed increase in water absorption from 60.3% to 76.3% with increase in the level of bran from 0% to 40%. The resistance to extension values as well as extensibility of the dough decreased with increase in the bran level. The spread ratio of the biscuits prepared from wheat, rice and oat bran blends decreased from 8.38 to 7.52, whereas the same increased to 9.3 for biscuits prepared from barley bran blends. The breaking strength values of biscuits ranged between 1.34 and 3.83 kg. Highly acceptable biscuits could be obtained by incorporating 30% of oat bran or 20% of barley bran in the formulation.     

Phenols,Flavonoids, and Antioxidant and Antibacterial Activity of Leaves and Stem Bark of Morus Species

Leaves and stem bark composition from Morus species (M. alba var. alba, M. alba var. rosa and M. rubra) was evaluated for its antioxidant and antimicrobial activities in order to enhance its therapeutic uses. Total phenolics and flavonoids contents were estimated in hydromethanolic and aqueous extracts. Results showed highest content in M. rubra leaves aqueous extract (1129 mg gallic acid equivalent/100 g dry weight and 816 mg gallic acid equivalent/100 g dry weight, respectively). Using 2,2-diphenyl-1-picrylhydrazyl assay, the highest antioxidant activity was obtained in aqueous stem barks extracts. M. alba var. alba has an IC₅₀ of 2.84 mg/ml and the IC₅₀ value of M. rubra was the highest (4.78 mg/ml). ABTS^.+ (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) method and reducing power assay were used to confirm the results from the 2,2-diphenyl-1-picrylhydrazyl test. All extracts expressed considerable free radical-scavenging properties. Hydromethanolic and aqueous extracts were tested against Staphylococcus aureus, Enterococcus feacalis, Staphylococcus epidermis, Escherichia coli, and Salmonella Typhimurium bacteria. Hydromethanolic stem bark extracts have the highest antimicrobial activities, and it may be a good antimicrobial agent for human gastrointestinal infections. This plant could be used as an additive to foods and also as a possible source to obtain new and effective herbal medicines to treat infections of multi-drug resistant strains of microorganisms.     

Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices

The aim of this work was to study the effect of temperature and air velocity on the drying kinetics and quality attributes of apple (var. Granny Smith) slices during drying. Experiments were conducted at 40, 60 and 80 °C, as well as at air velocities of 0.5, 1.0 and 1.5 m s⁻¹. Effective moisture diffusivity increased with temperature and air velocity, reaching a value of 15.30 × 10⁻⁹ m² s⁻¹ at maximum temperature and air velocity under study. The rehydration ratio changed with varying both air velocity and temperature indicating tissue damage due to processing. The colour difference, ΔE, showed the best results at 80 °C. The DPPH-radical scavenging activity at 40 °C and 0.5 m s⁻¹ showed the highest antioxidant activity, closest to that of the fresh sample. Although ΔE decreased with temperature, antioxidant activity barely varied and even increased at high air velocities, revealing an antioxidant capacity of the browning products. The total phenolics decreased with temperature, but at high air velocity retardation of thermal degradation was observed. Firmness was also determined and explained using glass transition concept and microstructure analysis.     

Apple pomace as a source of dietary fiber and polyphenols and its effect on the rheological characteristics and cake making

Apple pomace, a by-product of apple juice industry, is a rich source of fibre and polyphenols. Also in view of the antioxidant property of pomace, it would play an important role in prevention of diseases. Apple pomace procured from fruit juice industry, contained 10.8% moisture, 0.5% ash and 51.1% of dietary fibre. Finely ground apple pomace was incorporated in wheat flour at 5%, 10% and 15% levels and studied for rheological characteristics. Water absorption increased significantly from 60.1% to 70.6% with increase in pomace from 0% to 15%. Dough stability decreased and mixing tolerance index increased, indicating weakening of the dough. Resistance to extension values significantly increased from 336 to 742 BU whereas extensibility values decreased from 127 to 51 mm. Amylograph studies showed decrease in peak viscosity and cold paste viscosity from 950 to 730 BU and 1760 to 970 BU respectively. Cakes were prepared from blends of wheat flour containing 0–30% apple pomace. The volume of cakes decreased from 850 to 620 cc with increase in pomace content from 0% to 30%. Cakes prepared from 25% of apple pomace had a dietary fibre content of 14.2% The total phenol content in wheat flour and apple pomace was 1.19 and 7.16 mg/g respectively where as cakes prepared from 0% and 25% apple pomace blends had 2.07 and 3.15 mg/g indicating that apple pomace can serve as a good source of both polyphenols and dietary fibre.     

Phenolic profiles and cellular antioxidant activity of longan pulp of 24 representative Chinese cultivars

The phytochemical composition and antioxidant activity of fruits are associated with their health benefits. Longan is a traditional Chinese edible and medicinal fruit, but its varietal differences in phytochemical profiles and antioxidant activity were unknown. Twenty-four longan cultivars from southern China were investigated in this study. Their total phenolic and flavonoid contents in pulp were 22.09–132.47 mg gallic acid equivalents/100 g and 2.48–14.26 mg catechin equivalents/100 g, respectively. The mean contributions of free phenolics and ?avonoids to the total were 82.5% and 94.0%, respectively. Among 10 individual phenolics detected by HPLC, the contents of epicatechin, 4-methylcatechol, chlorogenic, and vanillic acids were relatively higher. The cellular antioxidant activity (CAA) of longan pulp showed significant varietal discrepancies and positive correlation with phenolic and flavonoid contents. Phenolics in longan pulp of 24 cultivars showed lower CAA potential than many other fruits with the CAA qualities from 0.35 to 1.21 µmol quercetin equivalent/100 µmol total phenolics. Longan cultivars were classified into six groups by hierarchical clustering analysis. Six cultivars in group 4 and 6 had higher phytochemical contents and CAA activity.     

Effect of enrichment with hemicellulose from rice bran on chemical and functional properties of bread

This paper examines the use of the defatted rice bran hemicellulose B (RBHB), and insoluble dietary fibre (RBDF), as two functional ingredients added to bakery products. The results show that the RBHB from defatted rice bran had high water-binding and swelling capacity. RBHB exhibited high fat binding capacity. However, RBHB was found to be low viscous. Addition of 1%, 2% and 3% RBHB preparation reduced loaf volume significantly and increased the firmness of the breads. Sensory evaluations revealed that breads with 1%, 2%, 3% RBHB and 2%, 4% RBDF were overall acceptable. This confirms that the RBHB and RBDF preparation from defatted rice bran has great potential in food applications, especially in development of functional foods including functional bakery products.     

Bioactivity of Greek honey extracts on breast cancer (MCF-7), prostate cancer (PC-3) and endometrial cancer (Ishikawa) cells: Profile analysis of extracts

Historically, honey has been important in Greek culture. The chemical composition and the potential of Greek honey extracts (thyme, pine and fir honey) to influence the oestrogenic activity and the cell viability of breast (MCF-7), endometrial (Ishikawa) and prostate (PC-3) cancer cells were investigated. All honeys contained total phenolics, phenolic acids and hydroxymethylfurfural, the levels being highest in thyme honey. Sugars and volatile compounds, but not fatty acids, were detected in all honey extracts. Thyme, pine and fir honey showed both antioestrogenic and a weak oestrogenic effect at low and high concentration, respectively, in MCF-7 cells. Thyme honey reduced the viability of Ishikawa and PC-3 cells, whereas fir honey stimulated the viability of MCF-7 cells. In conclusion, Greek honeys are rich in phenolic compounds, they modulate oestrogenic activity whereas a thyme honey-enriched diet may prevent cancer-related processes in breast, prostate and endometrial cancer cells.     

Effects of a mixed koji culture of Aspergillus oryzae HG‐26 and Aspergillus niger HG‐35 on the levels of enzymes,antioxidants and phenolic compounds in soy sauce during the fermentation process

Soy sauce contains a number of bioactive components, which have been shown to possess strong antioxidative properties. The objective of this study was to compare the enzyme activities, antioxidant activity and phenolic compounds content of soy sauces prepared from a mixed koji (SSAON, inoculated with Aspergillus oryzae HG‐26 and Aspergillus niger HG‐35), with those of soy sauces made from a koji culture containing only Aspergillus oryzae HG‐26 koji (SSAO). The total phenolic content (TPC), total flavonoid content (TFC), content of three isoflavone aglycones (daizein, glycitein and genistein) and the antioxidant activity of the SSAON were found to be higher than those of the SSAO during moromi fermentation. In addition, they showed strong positive correlations with the antioxidant potential of the soy sauce. This study has demonstrated the potential of a mixed‐culture koji, based upon A. orzyae and A. niger, for the production of soy sauce with an increased level of bioactive components.