Polyphenol contents and in vitro antioxidant activities of lyophilised aqueous extract of kiwifruit (Actinidia deliciosa)

The aim of this study was to determine the antioxidant potency and total phenolic and flavonoid contents of kiwifruit (Actinidia deliciosa) in vitro by analysing the radical scavenging activity of lyophilised water extract from kiwifruit (LEK) for 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl-hydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD), and superoxide anion radical (O₂⁻) as well as the total reducing power by FRAP and CUPRAC assays and the metal chelating activities. LEK showed efficient radical scavenging activity with DPPH, ABTS, DMPD, and O₂⁻ radicals; ferric (Fe³⁺) and cupric (Cu²⁺) ion reducing power and metal chelating activities. Moreover, the amounts of phenolic compounds, such as caffeic acid, ferulic acid, syringic acid, ellagic acid, catechol, pyrogallol, p-hydroxy benzoic acid, vanillin, p-coumaric acid, gallic acid, quercetin, ??-tocopherol and ascorbic acid, in LEK were quantified by LC-MS-MS. The results show that pyrogallol (2070.0 mg/kg LEK) is the main phenolic compound responsible for the antioxidant and radical scavenging activities of LEK. Finally, total phenolic and flavonoid contents were determined as gallic acid (GAE) and quercetin equivalents (QE). The GAE and QE values in LEK were 16.67 ± 2.83 ??g GAE/mg and 12.95 ± 0.52 ??g QE/mg, respectively. The results suggest that consumption of kiwifruit (A. deliciosa) can be beneficial effects due to its antioxidant properties.     

Effect of nanocomposite-based packaging on postharvest quality of ethylene-treated kiwifruit (Actinidia deliciosa) during cold storage

A novel nanocomposite-based packaging (NCP) was prepared by blending polyethylene (PE) with nano-Ag, nano-TiO₂ and montmorillonite. The effects of NCP on the quality parameters of ethylene-treated mature kiwifruit were investigated during the 42 d of storage at 4 °C. The results showed that adding nanoparticles to the PE significantly decreased the oxygen, water vapor permeability and longitudinal strength, and inhibited spore germination. The weight loss, softening, color variation and soluble solid content of kiwifruit were significantly inhibited by 22.67%, 124.84%, 23.46% and 14.42% respectively, which indicated that NCP could delay the ripening of kiwifruit. However, ascorbic acid and total phenols contents in NCP-treated fruit were increased compared with the controls. Additionally, kiwifruit in NCP exhibited 57.44% lower headspace ethylene concentration, 29.44% for malondialdehyde (MDA), lower polyphenol oxidase (PPO) activity and higher peroxidase (POD) activity than the controls. These results suggest that NCP may be a useful technique to reduce fruit decay and maintain quality in kiwifruits during postharvest storage.     

Analysis of chemical and structural changes in kiwifruit (Actinidia deliciosa cv Hayward) through the osmotic dehydration

Osmotic dehydration experiments of kiwifruit (Actinidia deliciosa cv Hayward) were carried out in order to apply a nonlinear irreversible thermodynamic model. Samples were immersed into 65% (w/w) sucrose aqueous solution at 30 °C during 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 250, 320, 400, 720, 1440 min. Some physical-chemical parameters were measured in fresh, treated and reposed (24 h at 30 °C) samples. It was possible to apply the enthalpy-entropy compensation coupled to a nonlinear thermodynamic model, obtaining the apparent bulk modulus and explaining the elastic answer of the tissue throughout the osmotic process. The osmotic dehydration also produces losses in the native compounds of kiwifruit such as citric acid and Calcium and Potassium.     

Combined effect of active coating and MAP to prolong the shelf life of minimally processed kiwifruit (Actinidia deliciosa cv. Hayward)

In this work different strategies aimed to prolong the shelf life of minimally processed kiwifruits are presented. First, the effectiveness of several treatments in delaying the quality loss of the investigated produce packaged under passive MAP was addressed; afterward, the treatments that have shown the best performances were used to assess the effectiveness of active MAP in prolonging the packaged produce shelf life. Different treatments such as coating with sodium alginate in combination with dipping into an hydro-alcoholic solution (Coat-dipp-EtOH), dipping into an hydro-alcoholic solution (Dipp-EtOH) and coating with sodium alginate containing grape fruit seed extract solution (Coat-GFSE) were investigated. The untreated samples were used as control. Headspace gas concentrations, pH, mass loss, sensory quality and viable cell load of main spoilage microorganisms were monitored in both the experimental steps. Results suggested that the best performances under passive MAP were recorded with the coating treatments, justifying the choice of this treatment in the second step. In fact, the coatings were more effective in delaying dehydration and slowing down respiratory activity of minimally processed kiwifruits both in passive and active MAP. The combination of active compounds with alginate-based coating delayed the microbial growth whereas the sole dipping treatment was inefficient. In particular, a viability loss of the mesophilic and psychrotrophic bacteria of about 2 log cycle for the coated samples with respect to control and dipped samples was found. However, as the microbial load was always found below the threshold value imposed by law, the sensorial acceptability limit of the packaged fresh-cut produce coincided with its shelf life. Alginate-based coating reduced respiratory activity, as well as sensory decay, increasing the sensorial acceptability limit of the samples packaged under passive MAP up to 12 days with respect to the control (8 days). For the samples packaged under active MAP, the coating treatments reduced the excessive dehydration of the produce due to the MAP conditions. In fact, when the active MAP was used alone a very short shelf life of the uncoated samples occurred (2.7 days). Whereas, the combined use of active MAP and coating treatments prolonged the produce shelf life up to 13 days.     

Effect of actinidin from kiwifruit (Actinidia deliciosa cv. Hayward) on the digestion of food proteins determined in the growing rat

This study aimed to determine the effect of dietary actinidin (provided as Hayward kiwifruit) on the gastric and small intestine digestion of six food protein sources in rats. For each protein source, two semi-synthetic test diets were formulated containing either freeze-dried Hayward kiwifruit (actinidin present) or freeze-dried Hort16A kiwifruit (actinidin absent). Actinidin activity is extremely low in Hort16A kiwifruit. Titanium dioxide was also included as an indigestible marker. Rats were fed freshly-prepared diets, euthanised and the gastric and ileal contents collected. The chyme and digesta samples were subjected to electrophoresis (SDS–PAGE), densitometry and titanium analysis and the degradability of individual proteins calculated. Dietary actinidin had no (p > 0.05) effect on the gastric degradability of zein and whey protein isolate but increased gastric degradability of beef muscle protein, gelatin, soy protein isolate and gluten by 40%, 60%, 27% and 29% units, respectively. Dietary actinidin had little or no effect on ileal protein degradability. Overall, dietary actinidin enhanced the gastric digestion of some food proteins.     

Effect of osmotic dehydration on Actinidia deliciosa kiwifruit: A combined NMR and ultrastructural study

The effects of individual osmotic dehydration processes (OD) on kiwifruit outer pericarp tissue were studied as reliant on treatment temperature (25, 35 and 45 °C) and extent (0–300 min). Macro (Low Frequency Nuclear Magnetic Resonance, LF-NMR), micro (Light Microscopy, LM) and ultrastructural (Transmission Electron Microscopy, TEM) measurements were performed to evaluate modifications of three cellular compartments, namely vacuole, cytoplasm – extracellular space and cell wall.     

Characterisation of bound volatile compounds of a low flavour kiwifruit species: Actinidia eriantha

Aroma compounds in fruit are known to occur in free and glycosidically bound forms. The bound volatile fraction of a low flavour kiwifruit species, Actinidia eriantha, was studied. The fruit have a bland and grassy flavour. Glycosidic precursors were isolated from juice by adsorption onto an Amberlite XAD-2 column. After enzymatic hydrolysis with Rapidase AR2000, the released aglycones were analysed by GC–MS. Alcohols, terpenoids and phenolics were the most numerously represented compound classes. Alcohols, benzenoids and phenolics showed the highest concentrations. Major compounds were 2-phenylethanol, furfuryl alcohol, (Z)-3-hexen-1-ol, coniferyl alcohol, isoamyl alcohol and linolenic acid. Several of the bound compounds found, including linoleic, linolenic and benzoic acids and coniferyl alcohol, are precursors of odorous volatiles. Many compounds detected as bound volatiles have not been previously reported as free volatiles in A. eriantha. The bound volatile composition of A. eriantha also showed differences with those of other kiwifruit species.     

δ-Tocomonoenol: A new vitamin E from kiwi (Actinidia chinensis) fruits

A new vitamin E, δ-tocomonoenol, has been isolated from Actinidia chinensis (kiwi) fruits. The new structure, 2,8-dimethyl-2-(4,8,12-trimethyltridec-11-enyl)chroman-6-ol, has been elucidated on the basis of EIMS, 1D, and 2D NMR spectral data. GC–MS analysis of peels and pulps of kiwi showed that the new compound, together with δ-tocopherol, is mainly present in the fruit peel, whilst α-tocopherol is present in a similar amount in both matrices. The compound was tested for its radical-scavenging and antioxidant capabilities, by measuring its ability to scavenge DPPH (2,2′-diphenyl-1-picrylhydrazyl radical) and anion superoxide radical, and inhibit the formation of methyl linoleate conjugated diene hydroperoxides and TBARS (thiobarbituric acid reactive species).     

The vitamin C content of some kiwifruits (Actinidia chinensis planch., variety hayward)

Skin, outer pericarp, inner pericarp and core, respectively comprised 4·8, 43·7, 45·0 and 6·5% of a mean whole kiwifruit weight of 111·3 ± 1·3 g. Kiwifruit weights ranged from 99·0 to 125·3 g. Vitamin C content per 100 g edible flesh ranged from 37·8 to 53·6 mg with means of 43·7 ± 1·7 mg for total vitamin C,41·9 ± 1·5 mg for ascorbic acid (AA) and 1·7 ± 0·4 mg for dehydroascorbic acid (DHA). Vitamin C contents were found to be at least half previously reported contents, possibly due to losses during storage and transportation from New Zealand. Total vitamin C concentrations per 100 g of skin, outer pericarp, inner pericarp and core were 41·7 ± 3·1 mg, 42·9 ± 2·0 mg, 45·5 ± 2·3 mg and 42·3 ± 2·6 mg, respectively. Outer and inner pericarp contained similar concentrations of both AA with 40·7 ± 1·7 mg and 42·7 ± 2·1 mg, and DHA with 2·1 mg and 2·8 ± 0·7 mg per 100 g tissue, respectively. Skin and core contained lower concentrations of AA with 28·1 ± 2·4 mg and 31·1 ± 2·2 mg, and correspondingly higher contents of DHA with 13·5 ± 2·4 mg and 11·2 ± 1·3 mg per 100 g tissue, respectively. Whole fruit weight correlated with DHA concentration in both skin (r = ?0·644) and core (r = ?0·693).     

Domestic processing effects on available carbohydrate content and starch digestibility of black grams (Vigna mungo) and chick peas (Cicer arietium)

Domestic processing effects on available carbohydrate contents and starch digestibility of black grams and chick peas were investigated. The food legumes were soaked in tap water and alkaline solution of sodium bicarbonate at 30 and 100 °C for 1–2 h before cooking under pressure. Total soluble sugars, reducing sugars and starch contents of black grams and chick peas were 9.64% and 9.83%, 0.78% and 0.83%, 43.0% and 44.3%, respectively. All these available carbohydrate contents of black grams and chick peas were reduced to various extents as a result of soaking and cooking. At 30 °C, 4.46% of total soluble sugars, 3.84% of reducing sugars and 6.86% of starch contents were reduced on soaking the black grams in tap water for 1 h. Available carbohydrate contents were further reduced when soaking time and temperature of the food legumes was increased before cooking. About 3.43–25.0% of total soluble sugars and 4.26–22.7% of starch contents were lost on soaking black grams and chick peas in tap water and sodium bicarbonate solution. Maximum amounts of total soluble sugars (28.5–59.6%) and starch contents (29.9–67.4%) were lost on cooking the water- and alkali-soaked food legumes. However, these losses were comparatively less with the water soaking process. Besides these losses, starch digestibilities of black grams and chick peas were markedly improved as a result of cooking. However, no appreciable improvement in the starch digestibility was observed after soaking these food legumes in water or alkaline solution.     

Effect of cold storage and ozone treatment on physicochemical parameters,soluble sugars and organic acids in Actinidia deliciosa

The production of kiwi fruits is a dynamic agricultural activity in Corsica (France). The fruits are either consumed directly or used to produce kiwi wine. They are often stored for 4–6 months in industrial freezer chambers at 0 °C or industrial ozone chambers. The aim of this study was to measure physical, chemical and fungicidal parameters, soluble sugars and non-volatile organic acids during storage in each of these types of chamber. Various standard and instrumental methods (physicochemical techniques, HPLC) in conjunction with statistical analysis were used. During storage, the kiwi mass, firmness and acidity decreased, whereas reducing sugar, °Brix and pH increased. There were statistical differences between the two chambers regarding reducing sugar and acidity. The ozone gas treatment had a fungicidal effect on Botrytis cinerea. The major soluble sugar present in the kiwi fruit was fructose, followed by glucose and sucrose. The concentrations of these sugars increased during storage in both air at 0 °C and ozone-enriched air. Organic acids are one of the important factors influencing fruit flavour. Citric and quinic acids predominated over malic, tartaric and ascorbic acids. During storage in the ozone chamber, concentrations of non-volatile organic acids decreased sharply after 25 weeks. Storage at 0 °C enabled better retention of organic acids.     

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.     

Application of microwaves dielectric spectroscopy for controlling osmotic dehydration of kiwifruit (Actinidia deliciosa cv Hayward)

Dielectric spectroscopy studies have been performed on fresh and osmotically dehydrated kiwifruits (Actinidia deliciosa cv Hayward). The osmotic treatment consisted on the immersion the samples into 65% (w/w) sucrose aqueous solution at 30 °C during different treatment times from 5 to 1440 min. Some physical–chemical parameters were measured in fresh, treated and reposed (24 h at 30 °C) samples. Dielectric spectra were measured in the frequency range from 500 MHz to 20 GHz by an Agilent 85070E Open-ended Coaxial Probe connected to an Agilent E8362B Vector Network Analyzer in the fresh, treated and reposed samples. It has been demonstrated that the dielectric technique is a good method to control the osmotic treatment in kiwifruit.Industrial relevance: The results of this research article are demonstrated to be useful for controlling candying of kiwifruits in bakery industries. Thus, the industrial relevance is clear in order to optimize the osmotic dehydration times and the final quantity of sugars added by using a non destructive technique that can be implemented in process line. Dielectric spectroscopy, which can be considered an emerging technology, has the advantage of being an objective and a rapid technique. For all these reasons we are sending to this journal “Innovative Food Science and Emerging Technologies” our results.     

Organic acids in two Portuguese chestnut (Castanea sativa Miller) varieties

The organic acids composition of two different chestnut (Castanea sativa Miller) varieties (Judia and Longal) were determined by HPLC/UV. In order to check the influence of the processing over these compounds, samples treated in three distinct manners (roasted, boiled and fried) were also analysed. The results showed that chestnut is characterized by the presence of seven organic acids: oxalic, cis-aconitic, citric, ascorbic, malic, quinic and fumaric acids. The organic acid quantitative profile allows the distinction of the two varieties. Longal variety samples presented higher organic acids contents than those from Judia variety. The contents of the pair malic plus quinic acids may be useful for the discrimination of the two varieties. Roasting, boiling and frying procedures lead to significant reduction of total organic acids contents.     

Chemical composition and characterisation of seeds from two varieties (pure and hybrid) of Aesculus hippocastanum

Investigations have been conducted on some samples of naturally desiccated horse-chestnuts (Aesculus hippocastanum), representative of the two most common mediterranean varieties: the pure species (AHP, giving white flowers), and a hybrid (AHH, giving pink flowers). Different experimental techniques have been used to gain more information on morphological structure and chemical composition of these complex matrices. Surface analysis by SEM showed no differences in such floured samples (wild type), while thermal behaviour (DSC) outlines some significant differences between them. Chemical composition reveals some differences in residual moisture (AHP = 6.97%; AHH = 6.59%), proteins (AHP = 2.64%; AHH = 1.82%), lipids (AHP = 4.13%; AHH = 5.10%), glucides (AHP = 15.2%; AHH = 14.3%), and ashes (AHP = 2.51%; AHH = 2.19%). Most likely, these characters modulate other undifferentiated chemical parameters, such as cold water solubility (CWS:AHP = 53.9%; AHH = 48.6%), and total inorganic soluble salts (TISS:AHP = 2.18%; AHH = 1.92%). Principal component analysis was applied to differentiate the two horse-chestnuts varieties. In particular, the first principal component effectively distinguish and discriminates AHH and AHP samples in two well-separated categories, giving, at the same time, some information on the influence of the whole set of chemical compositional parameters.     

Concordance between antioxidant activities and flavonol contents in different extracts and fractions of Cuscuta chinensis

Chinese herbs employed in traditional Chinese medicine (TCM) have been used for centuries in the practice of medicated diet and dietetic therapy. The seed of Cuscuta chinensis Lam. (Convolvulaceae), a commonly used traditional Chinese herb, is frequently added in Chinese cooking and preparation of refreshments, including porridge and alcoholic beverages, to nourish the human body. In the present study, we compared the antioxidant activities of water and ethanol extracts from the seeds C. chinensis and also of its different organic fractions, including n-hexane, ethyl acetate, n-butanol and organic water, by assessing their DPPH (1,1-diphenyl-2-picryl hydrazine) free radical-scavenging, superoxide anion scavenging, anti-superoxide anion formation and anti-lipid peroxidation abilities. The flavonol contents of all test samples were analyzed by high-performance liquid chromatography with an ultraviolet (HPLC–UV) detector. The results showed that there is a direct correlation of the flavonol content with the antioxidant activities from the extracts and fractions of C. chinensis. Moreover, the ethyl acetate fraction demonstrated significantly better and higher antioxidant effects, and also had a higher flavonol content than had the remaining samples (P < 0.05). The water fractions, however, exhibited the weakest antioxidant activity, and had low concentrations of flavonols. Thus, we suggest that the ethanol extract of C. chinensis, but not its water extract, could be used as a dietary nutritional supplement to promote human health and prevent oxidation-related diseases, due to its antioxidant properties.     

Antioxidant and radioprotective properties of commercially grown litchi (Litchi chinensis) from India

In an earlier study, radiation treatment (0.5 kGy) and low temperature (4 °C) storage were found to extend the shelf life of litchi fruit var. ‘Shahi’ and ‘China’ from India up to 28 days, while maintaining its physical, biochemical and organoleptic properties. The current study was aimed to elucidate the antioxidant and radioprotective properties of the litchi fruit, and the effect of radiation processing on these properties. The litchi fruit was found to be significantly rich in antioxidant and radioprotective properties, and the antioxidant parameters were found to be well correlated with the phenolic and flavonoid contents. A significant protection to pBR322 plasmid DNA and Escherichia coli cells from radiation induced damage was observed in the presence of litchi juice. Plasmid DNA was well protected even at the dose of 5 kGy, whereas, bacterial cells could be protected up to 0.5 kGy. Neither of these properties was found to be sensitive to radiation processing or low temperature storage.     

Determination of the melatonin content of different varieties of tomatoes (Lycopersicon esculentum) and strawberries (Fragariaananassa)

Melatonin has recently been detected in various plants and foods. However, data regarding the food composition of melatonin are too scarce to evaluate dietary intake. This paper aims to identify melatonin unequivocally using LC–MS in a wide set of varieties of tomatoes (Lycopersicon esculentum) and strawberry (Fragariaananassa). Furthermore, a validated LC fluorescence was developed.