An investigation into the physical properties of fibre prepared from several carrot varieties at different stages of development

Important physical properties of dietary fibre include water holding capacity (WHC) and cation exchange capacity (CEC). In this investigation fibre prepared from different varieties of the same species, the carrot Daucus carota, have been sampled at different stages of development to determine whether these physical properties were dependent upon variety and the age of the plant. Results for WHC (g g^?1 fibre) were dependent on the method of analysis. Differences found between varieties for WHC measured by centrifugation (mean 23.7 g, range 13.4–32.3) were not apparent when measured by filtration of a corresponding sample (mean 27.9 g, range 17.2–45.5). Differences between methods probably reflect structural differences in the fibre influenced by age and variety. Both methods showed carrot fibre to have a relatively high WHC. The CEC (meq g^?1 fibre) was found to be similar between varieties but to increase with age within each variety, (mean 1.44 meq, range 1.07–2.42). The type of exchange did not change and the CEC 100 g^?1 fresh carrot remained constant between varieties and also within each variety. The pK determined for each sample was between 4.42–5.30 which suggests pectins to be responsible for the CEC.     

Dietary fibre in some Norwegian plant foods during storage

The dietary fibre (DF) content of some storage-strong vegetables, grown in Norway, has been determined. The vegetables were collected at harvest time and at intervals during storage, to monitor the DF content during the storage season.Nantes, a variety of carrot, and Hygro, an onion variety, were available throughout the entire period of investigation. A slight decrease in the DF content with length of storage was observed for carrots, but not for onions.With cabbage (Golden Acre, Toten Amager and Blue Top varieties) and rutabaga (Gry and Bangholm varieties) any particular variety was available only for a shorter period (1–4 months), with little overlap between varieties. No systematic change in DF content was observed within any variety during this period. However, differences in DF content from variety to variety within the same vegetable were found.The observed DF variations within each vegetable, whether due to storage or to variety, were relatively slight and need not normally be taken into account when estimating the DF contents of diets containing these vegetables. Some methodological problems are discussed.     

Physico-chemical properties of cell wall materials obtained from ten grape varieties and their byproducts: grape pomaces and stems

The availability and the potential of wine by-products, grape pomaces and stems, obtained from ten different grape (Vitis vinifera L.) varieties (six red and four white) as raw materials for the production of dietary fibre (DF) concentrates were evaluated. The overall chemical composition, carbohydrate analysis and functional properties of DF from fresh grapes, grape pomaces and stems from those grape varieties were analysed. Both winemaking by-products presented considerable quantities of DF, ranging from 60% to 90% of total dry matter. The cell wall polysaccharides (CWP) composition of grape pomaces and fresh grapes was rather similar, pectic substances being the main component of the cell walls (40–54% total CWP). In contrast, cellulose was the predominant cell wall polymer for the stems (40–49% total CWP). In addition, the pectin content of grape pomaces exhibited significant differences between red and white grape varieties. The degree of methyl-esterification of uronic acids from wine by-products ranged from 21 to 39%; thus, pectic polysaccharides from the different samples could be classified as low methyl-esterified pectins. Klason lignin accounted for around 20–25% of DF in both grape pomaces and stems. With regard to the potential incorporation of DF concentrates into the food chain, functional properties were also determined. Swelling, water and fat retention capacity results showed great variability depending on the grape variety analysed.     

Variability of Some Physico-chemical Characters in Desi and Kabuli Chickpea Types

A collection of 50 chickpea accessions (26 kabuli and 24 desi types) was evaluated for 2 years for eight physico-chemical seed characters: 100-seed weight, hydration capacity, hydration index, coat thickness and contents of protein, oil, acid detergent fibre (ADF) and starch. Significant differences were found between desi and kabuli types for the majority of the characters. The variance component due to the genotype×year interaction was important for the hydration index, starch and protein content, showing the importance of the year effect on genotypic expression of these characters. One kabuli accession and five desi accessions with high and stable protein content were selected. There was no overlap between the variation limits of desi and kabuli for coat thickness and ADF content. There were high positive and significant correlations between seed weight and oil content for both types of chickpea.     

Cauliflower (Brassica oleracea L), globe artichoke (Cynara scolymus) and chicory witloof (Cichorium intybus) processing by-products as sources of dietary fibre

By-products arising from vegetable processing activities have been assessed in relation to their potential application as sources of dietary fibre supplements in refined foods. Sources used were fresh cauliflower, globe artichoke and chicory witloof. Non-starch polysaccharide (NSP) content and composition of selected parts of each plant source have been measured from alcohol insoluble residues (AIR) and by fibre analysis, complemented by methylation analysis to characterise structural features of component polysaccharides. Results indicate that cauliflower upper stem NSP was similar to the floret (∽25 g kg⁻¹ fresh weight) and each was rich in pectic polysaccharides. Cauliflower lower stem was enriched in NSP (∽66 g kg⁻¹) due mainly to cellulose and xylan deposition, which resulted in a proportionate decrease in pectic polysaccharides. Artichoke stem (∽38 g NSP kg⁻¹) was similar to the receptacle (∽34 g NSP kg⁻¹) but bracts were heavily lignified. Chicory root and leaf bud were each rich in pectic polysaccharides but NSP content was much higher in the root (∽46 g kg⁻¹) than the leaf (∽8 g kg⁻¹). Results indicate that processing by-products, eg cauliflower upper stem, artichoke stem and chicory root, could prove useful as sources of pectic polysaccharide-rich supplements. However, polysaccharide composition and glycosidic linkage pattern also identified important structural differences between sources. The importance of ‘fibre type’ when considering development of food supplements is discussed. © 1998 SCI.     

Dietary fibre content of table olives processed under different European styles: study of physico‐chemical characteristics

Some European varieties of olive fruit (Douro, Hojiblanca, Cassanese, Conservolia, Taggiasca, and Thasos), processed under different conditions (black oxidised, fermented in brine or dried by different methods) were analysed, their contents of moisture, fat and dietary fibre being quantified. The percentages of moisture and fat were very different between varieties due to the different processing conditions, although differences between samples of the same variety were much less. The content of dietary fibre was around 12% of the fresh weight, although in dried samples this percentage increased to around 20%. Some physico‐chemical characteristics (water holding capacity, cation exchange capacity, and ion retention capacity) were measured. The water holding capacities were related to moisture content, dry samples having the lowest values. Processed olives had very low cation exchange capacity in comparison to other vegetables, exhibiting the same relationship between this characteristic and moisture content. Olive fibre retained more iron than calcium under the assay conditions. © 2000 Society of Chemical Industry     

Dietary fibre and components of the nitrogen-free extract of almond kernels

Determinations of neutral and acid detergent fibre residues (NDF and ADF), hemicellulose, cellulose and lignin in almond nuts (Prunus amygdalus) were carried out. The NDF content was about 5% while the crude fibre content was only approximately 2%. The composition of several components of nitrogen-free extract (NFE) such as soluble sugars, starch, gums and mucilages and pectins were also determined, and the results are discussed.     

基于熵权法和灰色关联度法的鲜食糯玉米品质评价

为了研究不同品种鲜食糯玉米的品质特性,对17个不同品种鲜食糯玉米籽粒中的8个内在品质指标（水分、总淀粉、直链淀粉、支链淀粉、总糖、膳食纤维、粗蛋白、粗脂肪）含量和5项主要质构指标（硬度、弹性、内聚性、胶着性、咀嚼性）参数进行测定。通过相关性分析和主成分分析筛选出核心评价指标,在此基础上运用熵权法赋予各指标权重,最后采用灰色关联度法对鲜食糯玉米品质进行综合评价。结果显示,不同鲜食糯玉米品质存在一定差异性,质构指标与内在品质指标中的直链淀粉/支链淀粉含量均呈现较好的相关性;利用主成分分析筛选出4个核心评价指标,分别是支链淀粉含量、总糖含量、水分含量和粗脂肪含量。通过熵权法得到各核心指标的权重,其中支链淀粉含量的权重值最大。灰色关联度分析得出,综合品质较好的品种为万糯2000、苏科糯1702和苏科糯1505。此结果将为鲜食糯玉品质综合评价和品种筛选提供理论支持。     

Effect of Formulation on Physicochemical Properties and Water Status of Nutritionally Enriched Fresh Pasta

A standard fresh pasta formulation (STD, the control sample) was modified by introducing soy and carrot ingredients both in dry and in liquid forms (soy and carrot flour and soy milk and carrot juice) to obtain eight nutritionally enriched fresh pasta samples with different formulations. The effect of formulation on selected physicochemical properties and water status of fresh pasta were studied. Colour, texture (force at rupture and extensibility), and cooking loss were found significantly affected by the formulation. Soy and carrot decreased the force at rupture and extensibility of fresh pasta and increased the solids loss during cooking. Improper gluten network development due to either a steric hindrance of soy and carrot solids or improper water availability for gluten hydration due to different water–solid interaction developed were hypothesized. Soy and carrot ingredients significantly altered the water dynamics in the pasta matrix at different space-time levels (macroscopic, moisture content and water activity; macromolecular, frozen water content; molecular, proton nuclear magnetic resonance relaxometry) of fresh pasta in a manner dependent upon the physical state of the added ingredient. Soy flour increased both the frozen water content and the overall proton mobility (¹H FID, ¹H T ₁ and T ₂) of fresh pasta while these parameters did not markedly differed from STD when soy milk was used. The presence of both carrot flour and carrot juice decreased significantly the frozen water content of fresh pasta but, at a molecular level, carrot flour altered the proton molecular mobility, while carrot juice did not.     

Phenolic content and antioxidant activity of four date palm (Phoenix dactylifera L.) fruit varieties grown in Tunisia

Fruits of date palm ( Phoenix dactylifera L.) are consumed throughout the world and are a vital component of the diet in most Arabian countries. This study has been carried out to evaluate the total phenolic content and the antioxidant activity of four date palm fruit varieties grown in Tunisia. All measurements were made at the 'tamar' stage-the final stage of fruit ripeness. The date varieties were found to be rich in total phenolic ranging from 209.42 mg of equivalent gallic acid/100 g fresh weight in Kentichi to 447.73 mg equivalent gallic acid/100 g fresh weight in Allig. The date varieties studied were characterised by a high antioxidant activity ranging from 866.82 for the Deglet Nour to 1148.11 μmol Equivalent Trolox/100 g fresh weight for Khouet Kenta by the ABTS method. In fact, the DPPH method revealed that Allig having the lowest antioxidant activity (0.72) followed by Deglet Nour (1.53), Kentichi (1.68) and Khouet Kenta variety (1.96). This study suggest that Tunisian date palm fruit may serve as a good source of natural antioxidants and could potentially be considered as a functional food ingredient.     

Antioxidant Bioactive Compounds in Selected Industrial Processing and Fresh Consumption Tomato Cultivars

Four selected fresh consumption tomato varieties, harvested at different ripening stages (green, breaker, pink, red) and five industrial processing tomato varieties, harvested at red ripe stage, were analysed for lycopene and its isomers, β-carotene, total and individual phenolics, vitamin C and hydrophilic antioxidant activity. Tomato variety and ripening stage significantly affected carotenoids, total phenolic compounds and hydrophilic antioxidant activity when fresh consumption tomatoes were compared. The average of total lycopene content at the different ripening stages was 0.63, 12.20, 26.76 and 116.66 mg/kg of fresh weight (FW). Vitamin C ranged from 2.79 (breaker Cherry Pera) to 297.62 (red Cherry Pera) mg/kg FW. In green and breaker tomatoes, a positive correlation of hydrophilic antioxidant activity with vitamin C and chlorogenic acid was observed. However, in industrial tomato varieties (red ripe stage) and fresh consumption varieties harvested at pink and red stages, hydrophilic antioxidant activity was correlated with total phenolics and rutin. Tomato varieties for industrial processing did not show significant differences in total phenolic compounds and lycopene content. Lycopene ranged from 83.17 to 97.60 mg/kg FW, while total phenolic compounds varied between 257.91 and 284.13 mg/kg FW. Chlorogenic acid and rutin were the most abundant individual phenolics found in all the samples studied. Moreover, the content of total phenolics was always significantly correlated with the content of rutin. The amounts of all individual phenolics were affected by variety, with the exception of ferulic acid. Generally, these individual phenolics were more abundant in green and intermediate ripening stages, decreasing in full red tomatoes.     

The composition of pith from the sago palms Metroxylon sagu and Arenga pinnata

The tropical sago palms are increasingly regarded as having a major role as energy crops, but many aspects of them are little known. In this study samples of pith were obtained from Metroxylon sagu Roxb. in West Java and South Kalimantan, Indonesia, and from Arenga pinnata Merr. in West Java. Starch content of pith samples obtained from commercially harvested logs varied between 18.8 and 38.8% (fresh weight) for M. sagu and 10.5 and 36.7% for A. pinnata. However core samples of pith obtained in West Java from standing palms of M. sagu suitable for commercial use or from palms of similar dimensions and appearance, gave a much wider range of starch values; from 0.3 to 32.9% (fresh weight). Starch content was highly correlated with water content. Free sugars occurred at up to 5% (fresh weight) and in samples of very low dry matter content there was more sugar than starch. Predominant simple sugars were glucose, fructose and sucrose. Maltose was not detected. Crude protein and fat were negligible constituents. In addition samples were analysed for NDF, ADF, cellulose, lignin, ash, calcium, phosphorus, sodium and potassium. Pith residues obtained following starch extraction in village mills were found to contain significant amounts of starch.     

Effect of variety and crude protein content on nutrients and certain antinutrients in field peas (Pisum sativum)

Protein content was used as an indicator of environmental conditions for a study on varietal and environmental variation in proximate composition, minerals, amino acids and certain antinutrients of field peas. Four field pea varieties, each with three levels of protein content, were selected. Crude protein content overall ranged from 20.2 to 26.7%. Analysis of variance showed that both variety and environmental conditions had a significant effect on starch, acid detergent fibre (ADF), neutral detergent fibre (NDF) and fat content, but ash content was only affected by variety. Significant varietal and environmental differences in potassium (K), manganese (Mn) and phosphorus (P) were noted. Calcium (Ca) and copper (Cu) showed significant varietal differences, while iron (Fe), magnesium (Mg) and zinc (Zn) had significant environmental differences. Environmental conditions showed significant effects on alanine, glycine, isoleucine, lysine and threonine content. Variety had a significant effect on sucrose, raffinose and phytic acid content, whereas environmental conditions had an influence on trypsin inhibitor activity (TIA). The major pea components protein and starch were inversely correlated. ADF, NDF, Fe, Mg, Zn and the amino acid arginine were positively correlated with protein content. The amino acids glycine, histidine, isoleucine, lysine and threonine were negatively correlated with protein content. It was found that tryptophan was the most deficient amino acid and the sulphur‐containing amino acids were the second limiting amino acids in peas. Raffinose was positively correlated with sucrose but negatively correlated with verbascose. There were significant correlations between mineral contents and some of the proximate components. Copyright © 2004 Society of Chemical Industry     

Studies on growth,structural carbohydrate and phytate in coriander (Coriandrum sativum) during seed development

Coriander (Coriandrum sativum L) is an important spice crop and is used in Indian diets. Physiological characters of plants and biochemical constituents like structural carbohydrate and phytate were studied in developing coriander (var Narnaul and Panth) seeds. Moisture decreased with advancement of seed development. Neutral detergent fibre, acid detergent fibre, hemicellulose, cellulose and lignin levels increased with maturation of seed in both coriander varieties. Significant variations were observed in biochemical constituents between varieties and during different stages of seed development. The presence of phytate did not vary at different stages of seed development. The height of plants varied from 134 to 139 cm with 10 branches. Umbels varied from 89 to 99 with an average of six umbellets. Narnaul seed weight was double that of the variety Panth.     

Physico-chemical Properties, Vitamin C Content, and Antimicrobial Properties of Pomegranate Fruit (Punica granatum L.)

Pomegranate (Punica granatum L.) fruit is widely used in the food and process industries due to its excellent nutritional and health value and as a raw material for the manufacture of secondary products such as jellies, dyes, and cosmetics. The objectives of this research were to determine the vitamin C content and antimicrobial properties of fresh and dried fractions of fruit peel and arils of locally grown and imported pomegranate in Oman. A significant variation in vitamin C content was found among the five varieties of pomegranate studied, ranging from 52.8 to 72.0 mg/100 g fresh weight (fw) for arils and 76.8 to 118.4 mg/100 g fw for peels. Irrespective of the variety of pomegranate, vitamin C content in the peel was significantly higher than the aril, with differences ranging from 24.4% to 97.0% depending on variety. Fruit fractions showed antimicrobial effects (inhibition zone) on Staphylococcus aureus and Pseudomonas aeruginosa but not Escherichia coli. Sun drying of fruit peel significantly (p ≤ 0.05) enhanced vitamin C retention and antimicrobial effects in comparison with oven drying presumably due to lower rate of moisture removal associated with low temperature drying over longer duration in comparison with short-time high-temperature oven drying.     

Effects of variety and crude protein content on nutrients and anti-nutrients in lentils (Lens culinaris)

Protein content was used as an indicator of environmental conditions for a study on varietal and environmental variation of proximate composition, minerals, amino acids and anti-nutrients of lentils. Four lentil varieties, each with three levels of protein content, were selected. Crude protein content ranged from 24.3% to 30.2%. Analysis of variance showed that both varietal and environmental conditions had a significant effect on starch content. Significant varietal differences were found in acid detergent fibre (ADF), neutral detergent fibre (NDF), fat, ash, calcium (Ca), copper (Cu), potassium (K), manganese (Mn), phosphorus (P) and Zinc (Zn). Protein showed significant effects on the amino acids, arginine and tryptophan. Variety had a significant effect on sucrose, stachyose, phytic acid, tannins and trypsin inhibitor activity (TIA). Major lentil components, protein and starch content were inversely correlated. K, Mn, P and Zn were negatively correlated with protein content. Tryptophan was the most deficient amino acid and the sulphur-containing amino acids were the second limiting amino acid in lentils. Raffinose was positively correlated with starch while negatively correlated with ADF.     

Dietary fibre fractions from fruit and vegetable processing waste

Until recently, dietary fibre and its components were regarded as balast substances from vegetal food. These days, they are given increasing attention because of the beneficial physiological effects they may exert on human and animal organisms. Dietary fibre includes a number of components, and each of them displays specific properties. The components of major importance are cellulose, hemicellulose, lignin and pectins. The objective of this study was to determine the amounts of particular dietary fibre fractions in samples containing apple, black currant, chokeberry, pear, cherry and carrot pomace. The results revealed the following pattern: in each pomace sample, pectins occurred in the smallest amounts, and the content of lignin was very high (black currant and cherry pomace) or comparatively high (pear, chokeberry, apple and carrot pomace). The other dietary fibre components were difficult to form into clearly defined groups. Their proportions varied from one pomace type to another.     

Modification of in-vitro digestibility and cell-wall composition of cocksfoot,ryegrass and timothy by imazethapyr

Recent studies have shown that the compound imazethapyr (5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid) possesses growth regulatory activity and can be used to enhance nutritive value of grasses. However, little is known about possible effects of this material on fibre composition or potential fibre utilisation by ruminants. The objective of this research was to examine imazethapyr-treated cocksfoot (Dactylis glomerata L), ryegrass (Lolium perenne L × L multiflorum Lam), and timothy (Phleum pratense L) for possible treatment-induced changes in in-vitro digestibility and in concentrations of selected fibre constituents. Replicated field plots treated with imazethapyr at 0 (control) or 100 g ai ha^?1 during the vegetative (pre-elongation) stage of growth were harvested when controls were in the early stage of inflorescence emergence. Samples taken from treated plots 4 weeks post-treatment had higher in-vitro dry matter disappearance (IVDMD), lower neutral detergent fibre (NDF), lower acid detergent fibre (ADF), lower cellulose, lignin, and higher hemicellulose concentrations compared with controls. Imazethapyr treatment also reduced the concentration of p-coumaric acid in NDF, but had no effect on ferulic acid. The treatment effect on in-vitro NDF disappearance, however, was inconsistent among the grass species and was statistically non-significant (P = 0·10), implying that, under the conditions of this study, imazethapyr-related enhancements in IVDMD can be attributed primarily to a reduction in the amount of NDF and its associated constituents, as opposed to qualitative differences in NDF composition.     

The composition of maturing Omani dates

The composition of two varieties of Omani dates, fard and khalas, was determined as maturity progressed. Free sugars and dietary fibre content were examined in detail. High-performance liquid chromatography (HPLC) of the extracts showed that at the early green stage (Arabic kimri), dates contained small amounts of glucose and fructose. At the intermediate yellow (khalal) and red (rutab) stages, large amounts (500–565 g kg⁻¹ dry weight) of sucrose had accumulated, but no additional glucose or fructose was detected. At the final mature (tamar) stage, all sucrose was converted to glucose and fructose (>800 g kg⁻¹ dry weight). Dietary fibre, determined as non-starch polysaccharides (NSPs) by gas chromatography (GC), decreased from 250 g kg⁻¹ (kimri) to 50 g kg⁻¹ (tamar) on a dry weight basis. The principal monomers of NSPs were glucose, galactose, xylose, mannose, arabinose and rhamnose. On a dry weight basis, pectin, protein and ash contents decreased as the dates matured. On a fresh weight basis, changes in NSPs, pectin, protein and ash could be attributed to loss of moisture and the accumulation of sucrose initially, or of invert sugar later as maturation progressed. © 1999 Society of Chemical Industry     

Changes in organoleptic attributes and physical properties of carrot during hydrothermal treatment

This research is aimed at determining the effect of different hydrothermal treatments of carrot on its organoleptic attributes and physical properties determining texture. A preliminary evaluation was performed on seven carrot varieties, of which the three were selected for study: Bangor, Fayette and Nektarina. In hydrothermally treated carrot, significant differences were observed in the intensity of sweet taste, cooked taste, uniformity and intensity of orange colour, and in physical properties including force and energy of extrusion and the extrudability index (p<0.05). These properties were found to be dependent on both carrot variety and the manner of hydrothermal treatment. Under the experimental conditions applied, hydrothermal treatment of the whole carrot root with steam was found to be optimal and the highest general sensation in terms of organoleptic attributes was reported for the Bangor variety.