Effects of simulated digestion in vitro on cell wall polysaccharides from kiwifruit (Actinidia spp.)

Cell wall polysaccharides are resistant to digestion and absorption in the human small intestine and are considered to be delivered to the colon in a chemically unaltered state. In this paper, pulp from green and gold kiwifruit was subjected to in vitro upper-intestinal tract digestion and the chemical and physical changes to cell wall polysaccharides (dietary fibre) were investigated. Yields of insoluble fibre decreased slightly with simulated digestion while soluble fibre yields increased. Constituent sugar and glycosyl linkage analysis of the soluble and insoluble fibre fractions revealed that the chemical composition and structure of the non-starch polysaccharides remained largely unchanged. However, the degree of methylesterification of galacturonic acid residues present in the pectin-rich soluble fibre fractions of both fruit decreased with treatment; size-exclusion chromatography detected changes in the molecular weight profiles of these fractions. These changes may affect the physicochemical properties and fermentability of kiwifruit dietary fibre in the large intestine.     

Effect of candying on cell wall polysaccharides of plums (Prunus domestica L.) and influence of cell wall enzymes

“Ameixa d’Elvas” is a candied plum (Prunus domestica L.) produced by a traditional process, using fruits of a specific ‘greengage’ variety, “Rainha Cláudia Verde”. The candying process consists of boiling the intact plums in water for 15 min and then putting them in sugar syrup, which is successively concentrated until 75 °Brix. Although a loss of intercellular adhesion of parenchyma cells after boiling is observed, candied plums are able to recover their cell-to-cell adhesion, giving a final tissue with a consistency similar to that observed for the fresh fruit. In order to explain this observation, cell wall polysaccharides of plums harvested in two orchards, Vila Viçosa (VV) and Cano (CA), from the same geographic region and at the same stage of ripening, were analysed fresh, boiled and candied. Plum cell walls are composed mainly of pectic polysaccharides and cellulose that, during the boiling step, are degraded and solubilised. Highly esterified pectic polysaccharides undergo gelation inside the fruits in the presence of sucrose, leading to the recovery of the fruit’s consistency. During the candying process diffusion of these methylesterified pectic polysaccharides to the sucrose syrup increase the syrup viscosity. The activity of pectin methylesterase, polygalacturonase, and cellulase of fresh fruits explains the observed higher extension of degradation of cell wall polysaccharides of the CA plum tissues after boiling. This higher degradation seems to prevent the complete recovery of the parenchyma cell structure, which was observed for the less degraded polysaccharides of VV plums.     

Study on bioaccessibility of betacyanins from red dragon fruit (Hylocereus polyrhizus)

Food Science and Biotechnology - Betacyanins are bioactive dietary phytochemicals which can be found in red dragon fruit (RDF). Therefore, the bioaccessibility of betacyanins that present in...     

Spray drying of red (Hylocereus polyrhizus) and white (Hylocereus undatus) dragon fruit juices: physicochemical and antioxidant properties of the powder

This study aims to investigate physical stability and antioxidant properties of spray‐dried red (Hylocereus polyrhizus) and white (Hylocereus undatus) dragon fruit powder upon storage at various relative humidity (RH). Inlet air temperatures of 120 °C (red dragon fruit) and 110 °C (white dragon fruit) as well as maltodextrin concentration of 30% (w/v) were selected as the spray drying conditions as powder was obtained at these minimum conditions. The powder was ranging from 3 to 7 μm in particle size with spherical morphology. The powder had lower antioxidant content and antioxidant activities compared with the control before spray drying. Storage of powder at 43%, 54% or 75% RH at 25 °C for 25 days resulted in structural changes correlating to the depression of glass transition temperatures (T_g) to below storage temperature. At 33% RH, no visible structural changes were observed. Antioxidant properties of the powder remained unchanged after 25 days' storage at the studied RHs.     

Comparing physicochemical properties of banana pulp and peel flours prepared from green and ripe fruits

Banana pulp and peel flour prepared from green and ripe Cavendish banana were assessed for physicochemical properties such as pH, total soluble solids (TSS), water holding capacity (WHC) and oil holding capacity (OHC) at 40, 60 and 80 °C, colour values L^∗, a^∗ and b^∗, back extrusion force (BEF) and viscosity. Data obtained were analysed by MANOVA, discriminant analysis and cluster analysis. All statistical analyses showed that physicochemical properties of flour prepared from pulp and peel, and green and ripe banana were different from each other. TSS, WHC40, WHC60 and BEF can be used to discriminate between peel and pulp flour, whilst TSS and viscosity can be used to discriminate between flour prepared from green and ripe banana.     

Comparison of post‐germination mobilization of cell wall polysaccharides and non‐cell wall carbohydrates in soybean (Glycine max L.) cotyledons

BACKGROUND: In previous research, we demonstrated that cell wall polysaccharide (CWP) levels of soybean (Glycine max L.) cotyledons are negatively correlated with the sum of seed oil and protein content. Although the results suggest that reducing cotyledon CWP levels would be desirable, it is not known whether CWP are mobilized during early seedling growth and, if so, to what extent mobilization contributes to seed reserves. RESULTS: Ungerminated (dry) seeds contained equivalent amounts [approximately 20 mg (cotyledon pair)^?1] of non‐cell wall carbohydrates (NCWC) and CWP. Galactose and arabinose accounted for 47% of total CWP in cotyledons of dry seeds. Measured 14 days after planting (DAP), the levels of NCWC and CWP were reduced 98% and 34%, respectively, in cotyledons of seedlings grown under a 16‐h photoperiod. Measured 14 DAP, greater than 85% of cotyledon cell wall galactose plus arabinose was mobilized. The transformation of the cotyledon to a photosynthetic organ was associated with restructuring of the cell wall involving increases in uronic acids, glucose and rhamnose. CONCLUSION: CWP of soybean cotyledons are modified during early seedling growth due to mobilization and cell wall restructuring triggered by light. The amount of carbon mobilized makes only a small contribution to total cotyledon reserves. Published 2009 by John Wiley & Sons, Ltd.     

Chemical composition of fruits in some rose (Rosa spp.) species

Fruits of Rosa canina, Rosa dumalis subsp. boissieri, Rosa dumalis subsp. antalyensis, Rosa villosa, Rosa pulverulenta and Rosa pisiformis were assayed for total phenolics, ascorbic acid, total soluble solids, total dry weight, total fat, fatty acids, pH, acidity, moisture, fruit colour and macro- and micro-elements. The highest total phenolic content was observed in Rosa canina (96 mg GAE/g DW). Rosa dumalis subsp. boissieri had the highest total fat content (1.85%), followed by Rosa pulverulenta (1.81%) and Rosa canina (1.78%), respectively. Nine major fatty acids were determined in rose species and α-linolenic acid was found to be dominant for all species. Total soluble solids, total dry weight, moisture and ascorbic acid contents of rose species varied from 29.42% (Rosa villosa)–37.33% (Rosa dumalis subsp. boissieri), 33.85% (Rosa villosa)–40.35% (Rosa dumalis subsp. boissieri), 59.65% (Rosa dumalis subsp. boissieri)–66.15% (Rosa villosa) and 727 mg/100 g FW (Rosa villosa) and 943 mg/100 g FW (Rosa dumalis subsp. boissieri), respectively. Nitrogen and mineral compositions of the rose species, e.g., N, P, K, Ca and Mg, were (averagely): 1.26%, 513 mg/100 g DW, 639 mg/100 g DW, 196 mg/100 g DW and 114 mg/100 g DW, respectively. The present study shows that the native rose genotypes are extremely rich sources of phenolics, carbohydrates and ascorbic acid, demonstrating their potential use as a food or food additive.     

Physico-chemical and structural changes of red-fleshed dragon fruit (Hylocereus polyrhizus) during fruit development

BACKGROUND: Determination of physico‐chemical (weight, length, diameter, stomatal density, respiration rate, colour, soluble solids concentration, titratable acidity, chlorophyll and betacyanin content) and structural changes of red‐fleshed dragon fruit (Hylocereus polyrhizus (Weber) Britton & Rose) was carried out from 5 to 35 days after pollination (DAP) in order to explain their growth, development, maturations and ripening stages. RESULTS: Fruit growth of red‐fleshed dragon fruit followed a sigmoid growth pattern. Significant changes in colour were obtained in both peel and pulp as DAP progressed, which were indicated by reductions of L*, C* and h° values as both changed from green to red–violet colour at ripening. Red–violet betacyanin was manifested earlier in pulp at 25 DAP, followed by peel 4–5 days later, and finally both peel and pulp turned full red–violet by 30 DAP. There was a significant increase in soluble solids concentration and titratable acidity with the continuous increase in betacyanin content as DAP progressed. CONCLUSION: The physico‐chemical and betacyanin accumulation of red‐fleshed dragon fruit changed as it developed, matured and ripened which coincided with structural changes. Copyright © 2010 Society of Chemical Industry     

Impact of Thermal Treatment on Physicochemical, Antioxidative and Rheological Properties of White-Flesh and Red-Flesh Dragon Fruit (Hylocereus spp.) Purees

White-flesh (Hylocereus undatus; WF) and red-flesh (Hylocereus polyrhizus; RF) dragon fruit purees were subjected to heat treatment for 0 to 60 min at temperatures between 50 and 90 °C. The influence of the different heat treatments on the physicochemical properties, colour, betacyanins content, microbial destruction, antioxidative properties and rheological parameters were investigated. The physicochemical values and antioxidative properties of the unheated RF were significantly higher than that of the unheated WF (p?<?0.05). The betacyanins content of RF after 90 °C for 60 min decreased to 32.35%, based on the initial puree. Total colour change (TCC) and betacyanins degradation followed the second-order kinetic. The L* and b* values of the purees can be recommended as an online quality control (R ²?≥?0.7733) and TCC of RF can be used to predict the betacyanins content (R ²?=?0.9442). The antioxidative properties of the heated WF and RF increased with heating treatment. The linear correlation among the antioxidative properties was strong (R ²?≥?0.8587). WF and RF showed shear thinning behaviour. After heating, the apparent viscosity of WF and RF increased and all cases fitted very well with the power law model (R ²?≥?0.9988). Thus, the heated dragon fruit purees, particularly the RF, offer possibilities to be applied in foodstuffs due to their interesting physicochemical properties and nutritional attributes after thermal treatment.     

Dragon fruit peel extract microcapsule incorporated pearl millet and dragon fruit pulp powder based functional pasta: formulation,characterization, and release kinetics study

Food Science and Biotechnology - The pearl millet based functional pasta was formulated by incorporating freeze dried dragon fruit pulp powder and 2% (w/w) microcapsule containing dragon fruit peel...     

Comparative study on the carotenoid composition of the peel and the pulp of different citrus species

The carotenoid compositions of the peel and the pulp of various citrus fruits were compared with HPLC methods using C18 and C30 columns. The extracts usually contain β-cryptoxanthin and lutein in considerable amounts and in all species except lime, the red apocarotenoid β-citraurin as well. In case of lime and mandarin the carotenoid compositions of peel and pulp show a good coincidence while in orange, clementine, grapefruit, lemon and kumquat there are a lot more differences. Lime extracts contain practically only two carotenoids: β-carotene and lutein. The carotenoid components of the saponified extracts of kumquat were separated on calcium carbonate columns and were investigated in detail. The components were identified with HPLC–DAD and HPLC–MS.Industrial relevanceCitrus fruits are important starting materials for juice production. Their carotenoid fingerprint shows differences not only in different species but the proportion of certain pigments can be different in the same fruit according to where the plants were grown and how they were processed. Comparison of the carotenoid content of different fruit products (e.g. juices) can give us useful hints about the quality of the product and about the amount of these important natural antioxidants.     

Phytochemical composition,cellular antioxidant capacity and antiproliferative activity in mango (Mangifera indica L.) pulp and peel

Cellular antioxidant activity (CAA) and inhibition of hepato‐cellular carcinoma (HepG2) proliferation were evaluated for the first time in the pulp and peel of mango cultivars. Comparatively, peel had high flavonoids and tocopherols content and showed significant antioxidant activity. Among all the studied cultivars, the Xiao Tainong peel was predominant with highest fistein, mangiferin and alpha‐tocopherol content and significant cellular antioxidant activity value 2986 ± 380 μmol QE/100 g FW. The HepG2 cells antiproliferation was maximum in the peel of Da Tainong and pulp of Aozhou with lowest EC₅₀ values, 2.35 ± 0.65 (peel) and 185.4 ± 10.9 (pulp) mg mL^?1, in a dose‐dependent manner. Negative associations of flavonoids and tocopherol compounds with CAA and antiproliferative activity in mango confirmed synergistic, additive or antagonistic actions of phytochemicals. The current study suggests that mango peel could be used as a value added ingredient or functional food and may contribute considerably to promote consumer health.     

Polyphenol composition and antioxidant capacity in pulp and peel of apricot fruits of various varieties and maturity stages at harvest

Polyphenol composition and antioxidant capacities of peel and pulp tissues of six apricot varieties were determined. Variations in polyphenol and antioxidant capacity based on variety (early‐maturing varieties and late‐maturing varieties) and harvest maturity (green mature and full mature) were assessed. The results of principal component analysis revealed that (+)‐catechin made the most important contributions to the antioxidant capacities of the pulp. As the (+)‐catechin content in ‘Dajie’ apricot decreased by 36.8% from green mature to full mature, the antioxidant capacities determined by ABTS free radical scavenging assay, DPPH free radical scavenging assay and cupric ion reducing antioxidant capacity assay decreased by 50.0%, 45.2% and 45.8%, respectively. Levels of phenolic compounds in the apricot peels were approximately 2–4 times higher than those of the pulps. Quercetin‐3‐rutinoside may be substantially responsible for the antioxidant capacities of the peels. The late‐maturing varieties tended to have higher levels of phenolic compounds and higher antioxidant capacities than the early‐maturing varieties. The antioxidant capacities in green mature apricots were much higher than those of full mature apricots.     

Polyphenol composition of peel and pulp of two Italian fresh fig fruits cultivars (<Emphasis Type="Italic">Ficus carica</Emphasis> L.)

An analytical study was carried out on phenols in two fig cultivars (Ficus carica L.), one black and one green. Fresh fruits were peeled and phenols were extracted separately from the peel and the pulp. The extracts were subjected to HPLC-DAD analysis, by monitoring at four wavelengths, 280, 316, 365 and 520 nm for catechins and benzoic acids, hydroxycinnamic acids, flavonols and anthocyanins, respectively. Results showed that phenols are concentrated almost exclusively in the peel, with the black cultivar having the highest content. In particular, the peel was rich in rutin, with amounts from 527 to 1,071 mg/kg (fresh basis) for green and black figs, respectively. The peel of black figs showed an appreciable content of cyanidin 3-O-rutinoside. The pulp of both green and black cultivars contained only cyanidin 3-O-rutinoside, while the cyanidin 3-O-glucoside was found only in the peel of the black figs. Chlorogenic acid and another cinnamic acid were detected in the peel of both cultivars, while benzoic acids and catechins were not present. Alessandra Del Caro and Antonio Piga contributed equally to this study.     

Influence of drying conditions on colour,betacyanin content and antioxidant capacities in dried red-fleshed dragon fruit (Hylocereus polyrhizus)

In this study, drying of red-fleshed dragon fruit at different temperatures (40, 50, 60, 70 and 80 °C) and air velocities (1.0 and 1.5 m s⁻¹) was conducted under the specific humidity of 25 g H₂O kg⁻¹ dry air. The results showed that drying at higher temperatures resulted in shorter drying times. However, temperature and air velocity did not significantly affect the total betacyanin contents and antioxidant capacities in dried products. Seven betacyanins identified by LC-MS were betanin, isobetanin, phyllocactin, isophyllocactin, betanidin 5 –O-(6′O-3-hydroxybutyryl)-β-glucoside, isobetanidin 5 –O-(6′O-3-hydroxybutyryl)-β-glucoside and decarboxylated phyllocactin. In addition, the temperature increased the isomerisation of betacyanins. The most preferable condition for preserving the colour and betacyanin contents of red-fleshed dragon fruit was the drying at a temperature of 80 °C and air velocity of 1.5 m s⁻¹ since it could shorten the drying time and give a bright red colour to the dried product as well as it had no significant impact on the betacyanins.     

Antioxidant capacity, phenolic content and vitamin C in pulp, peel and seed from 24 exotic fruits from Colombia

Twenty-four exotic Colombian fruits were evaluated for antioxidant activity and total soluble phenolics (TP) (edible part, seed and peel) and ascorbic acid content (edible part). The antioxidant activities were evaluated by ABTS (free radical-scavenging capacity) and FRAP (ferric reducing antioxidant power) methods. The ABTS, FRAP, TP and ascorbic acid values in the edible part were 3.25 to 175 ??M Trolox equiv/g fresh weight (FW), 6.29 to 144 ??M Trolox equiv/g FW, 15.7 to 1018 mg gallic acid equiv/100 g FW, and 0.53 to 257 mg ascorbic acid/100 g FW respectively. There were positive correlations between antioxidant activity (assessed by both ABTS and FRAP) and TP and ascorbic acid with the FRAP and ABTS methods. The edible part of banana passion fruits (P. tarminiana and P. mollisima) exhibited the highest values of antioxidant activity and total phenolics, while the highest level of ascorbic acid was recorded in the edible part of guava apple and cashew. The seeds with the highest values of antioxidant activity and total phenols were cashew, algarrobo, arazá and coastal sapote, while the peel of coastal sapote and algarrobo had the highest values of antioxidant activity and total phenolics. To the best of our knowledge, this paper reports the first evaluation of pulp, seed and skin of Colombian tropical fruits with a view to their knowledge utilization for the development of novel functional food products.     

Effect of the temperature of extraction on the composition of cell wall polysaccharides in olives

A comparative study of methods for isolating cell wall material from olives (variety Hojiblanca) was performed. Treatment with cold (T-1) or hot (T-2) ethyl alcohol was followed by extraction into cold or hot water (water-soluble fraction). The insoluble residues were delignified. Hemicelluloses A and B were isolated and the neutral sugar composition and protein content of the different fractions were determined. In the delignified fractions following treatments T-1 and T-2, hemicelluloses A were composed of 87.35% and 87.37% xylose, respectively, indicating the presence of a pure xylan. In the non-delignified fraction, the content of hemicelluloses B was higher than in the delignified fraction and its predominant sugar was glucose, although significant amounts of xylose, galactose and arabinose were also found. The study suggests that treatment T-1 gives better results than T-2 and that a higher degree of purification of hemicelluloses A is obtained from the delignified cell wall material, as well as a decrease in the proteins bound to the fractions.