Degradation of carotenoids in pumpkin (Cucurbita maxima L.) slices as influenced by microwave vacuum drying

The aim of this study was to investigate the influence of microwave vacuum drying on carotenoids in pumpkin (Cucurbita maxima L.) slices. Carotenoids were measured using the reverse-phase high-performance liquid chromatography technique. It was shown that compared with hot air drying, microwave vacuum drying inhibited color changes and significantly (p < 0.05) improved total carotenoid retention (89.1%) in pumpkin slices. During the microwave vacuum drying process, microwave power had an important effect on total carotenoid and all-trans carotenoids. As microwave power increased, the total carotenoid content significantly decreased (p < 0.05), and the levels of individual carotenoids, including all-trans-α-carotene, all-trans-β-carotene, and all-trans-lutein, generally decreased. However, there was an overall upward trend for the levels of 13-cis-β-carotene, 15-cis-β-carotene, 9-cis-β-carotene, and 9-cis-α-carotene. The trans carotenoid quality of the finished products was improved within a certain range of vacuum levels. In addition to the degradation induced by microwave energy, isomerization was considered to be responsible for the loss of all-trans carotenoids. These results indicated that inappropriate drying methods and conditions might result in high losses of all-trans carotenoids in pumpkins.     

Amino acid composition and antioxidative properties of hydrolysed pumpkin (Cucurbita pepo L.) oil cake protein

Pumpkin oil cake protein isolate (POCPI) was hydrolysed using two food-grade enzymes alcalase and trypsin. Alcalase-hydrolysed POCPI (POCPH₁) was selected as the optimum treatment based on the DPPH radical scavenging, total antioxidative, and ferrous ion chelating activities. Amino acid composition showed a direct relationship between the antioxidative activity of POCPH₁ and the amount of hydrophobic amino acids that formed 33.49% of its total amino acids. Surface hydrophobicity decreased as a result of hydrolysis and potent thermal and pH stability was observed in POCPH₁ (p ? 0.05). In terms of molecular weight distribution, size exclusion chromatogram indicated that the majority of peptides possessed molecular weight less than 6.5 kDa. Based on the results, POCPH₁ could be employed as a natural antioxidative agent with strong pH and thermal stability.     

Comparisons of physicochemical properties and antioxidant activities among pumpkin (Cucurbita moschata L.) flour and isolated starches from fresh pumpkin or flour

Physicochemical properties (pasting and thermal properties, swelling power, water solubility and antioxidant activities) and chemical composition of pumpkin flour (PF) and starches, isolated from fresh pumpkin (SFF) or flour (SFP) were compared. SFP and SFF had similar proximate composition and amylose content. Drying process during PF preparation modified starch properties. PF exhibited greater antioxidant activities (DPPH, ABTS and FRAP), but had lower β‐carotene than fresh pumpkin. SFF and SFP had higher amylose content than PF, and exhibited a B‐type X‐ray diffraction pattern with spherical and dome‐like starch granules. Peak viscosity of SFP was relatively higher than that of SFF, probably due to lower swelling power and water solubility, which indicated increased granular rigidity in the SFP starch structure. Compared with SFF and SFP, PF had significantly higher onset (T_o), peak (T_p) and conclusion (T_c) temperatures due to a lower starch content and relatively higher fibre content, which resulted in lower gelatinisation enthalpy (ΔH).     

Comparison of hot air-drying and freeze-drying on the physicochemical properties and antioxidant activities of pumpkin (Cucurbita moschata Duch.) flours

Freeze-drying and hot air-drying were applied in the preparation of pumpkin flours to investigate the effects of drying methods on the antioxidant activities and physicochemical properties. The antioxidant activities of methanol extracts from pumpkin flours were studied in terms of total antioxidant activity, reducing power, free radical scavenging, superoxide anion radical scavenging and metal chelating activities. Hot air-dried pumpkin flour showed stronger antioxidant activities than freeze-dried flour. The percentage inhibition of peroxidation in linoleic acid system by 15 mg mL⁻¹ extracts from hot air-dried and freeze-dried pumpkin flours was found to be 92.4% and 86.1% after 120 h of incubation, respectively. Hot air-dried pumpkin flour exhibited higher reducing power, free radical scavenging and metal chelating activities than freeze-dried flour. This study also indicated that freeze-drying significantly reduced the browning and preserved the redness of pumpkin flours. Hot air-drying reduced the oil absorption capacity, water absorption and porosity of pumpkin flours, while it markedly increased the water solubility and bulk density.     

The beneficial effects of Pumpkin (Cucurbita pepo L.) seed oil for health condition of men

Pumpkin seed oil, a dark greenish red oil, extracted from Cucurbita pepo L. oval seeds, is rich in essential highly unsaturated fatty acids with predominant oleic and linoleic acid content, and phytosterols. The aim of this review article was to evaluate the efficacy of pumpkin seed oil in men’s health. We used the clinical trials on the efficacy of pumpkin seed oil on different health conditions of men. The clinical trials were focused on the administration of pumpkin seed oil as alternative treatment in Benign Prostatic Hyperplasia (BPH), overactive bladder, and androgenic alopecia. The effects of the oil are related to phytoestrogens and unsaturated fatty acids content. The proposed mechanisms related to these efficacies are due to its inhibitory effects on 5-α-reductase, anti-inflammatory effects or the ability to scavenge free radicals. Also, relaxation effects on bladder sphincter may help the patients with difficulties in urination. Therefore, there is a need for further evaluation of these and other biological effects of pumpkin seed oil in pharmacological and clinical trials.

Abbreviations: Benign Prostatic Hyperplasia (BPH), Dihydrotestosterone (DHT), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), overactive bladder system score (OABSS), Aspartate Aminotransferase (AST), Alanine transaminase (ALT), y-glutamyltransferase (GGT), prostate specific antigen (PSA), phosphodiesterase type 5 (PDE-5)

Practical applications: The seeds, fruits, and leaves are used ethnobotanically as functional food. The seeds oil are rich in phytosterols (desmosterol, campesterol, stigmasterol, β-sitosterol, spinasterol, D7,22,25-stigmastatrienol, D7-stigmastenol, D7,25-stigmastadienol, and D7-avenasterol), fatty acids, squalene, tocopherols, and other healthy components. The components make it as alternative medicine for management of health in men. It has beneficial effects on Benign Prostatic Hyperplasia, over active bladder, and androgenic alopecia.     

Total phenolic compounds and antioxidant capacities of major fruits from Ecuador

Seventeen fruits from Ecuador were analysed for total soluble phenolic compounds content and for antioxidant capacity, using three different methods (DPPH, FRAP and ABTS⁺). For the total phenolic content measured by the Folin–Ciocalteu method, three groups, having <100, 200–500 and >1000 mg GAE/100 g FW, were clearly distinguishable. Andean blackberry, capulí cherry peel and banana passion fruit were classified in the third group, with concentrations of 2167, 1494 and 1010 mg of GAE/100 g FW, respectively. Antioxidant capacity analyses revealed the same classes. FRAP and ABTS⁺ gave comparable results and were highly correlated (y = 0.691x + 6.78; r² = 0.908). Spectrophotometric measurements showed that the Andean blackberry and capulí peel but not banana passion fruit contained high levels of anthocyanins (λ_max = 520 nm).     

Physicochemical and functional properties of whole and defatted meals from Mexican (Cucurbita pepo) pumpkin seeds

Chemical composition and some functional and thermal properties in whole pumpkin seed meal (WPSM) and defatted pumpkin seed meal (DPSM) were determined. The DPSM exhibited higher water absorption capacity (3 g H₂O per g sample), water solubility capacity (8.75%), oil absorption capacity (2.73 g oil per g sample), emulsifying capacity (61.71%), foaming capacity (51.92%) and gelling capacity (12% w/v) than the WPSM. The DPSM also had better swelling power (3.33% at 60 °C, rising to 4.31% at 90 °C), higher phase transition temperatures (T₀ = 80.04 °C, T_p = 86.50 °C and T_f = 93.20 °C) and a higher phase transition energy (0.93 J g^?1). However, the WPSM had higher bulk density (0.57 g cm^?3) and better foam stability (from 30 to 120 min). Micrographs showed defatting to cause microstructural changes in meal starch granules and proteins. Its high protein content makes the DPSM a potential alternative input in the food industry.     

Production of enzymatic hydrolysates with antioxidant and angiotensin-I converting enzyme inhibitory activity from pumpkin oil cake protein isolate

Protein isolate from pumpkin oil cake (PuOC PI) was hydrolysed by alcalase, flavourzyme and by sequential use of these enzymes, respectively, and the antioxidant properties and angiotensin-I converting enzyme (ACE) inhibitory activities of hydrolysates were evaluated. Under the same reaction conditions, alcalase hydrolysates showed a higher degree of hydrolysis (DH) than did flavourzyme hydrolysates. The highest DH’s by individual enzymes were 53.23 ± 0.7% and 37.17 ± 1.05%, respectively, both at 60 min. The increase of radical scavenging activity (RSA) in hydrolysates was positively correlated with the increase of DH, for both enzymes, though hydrolysates with flavourzyme showed two- or three-fold lower RSA than with alcalase. The highest bioactive potential was determined in the alcalase hydrolysate at 60 min, with RSA being 7.59 ± 0.081 mM TEAC/mg and ACE-inhibitory activity 71.05 ± 7.5% (IC₅₀ = 0.422 mg/ml). When this hydrolysate was further hydrolysed by flavourzyme, DH increased up to 69.29 ± 0.9%, but lower RSA (4.82 ± 0.21 mM TEAC/mg) and ACE-inhibitory activity (55.81 ± 6.196%) were determined in the final hydrolysate. This study suggested that the PuOC proteins could be converted into protein hydrolysates with antioxidant and ACE-inhibitory activities by enzymatic hydrolysis. Alcalase was shown as promising enzyme in further development of bioprocesses for the production of new bioactive food ingredients.     

Antioxidant activity of polyphenol and anthocyanin extracts from fruits of Kadsura coccinea (Lem.) A.C. Smith

Polyphenols and anthocyanins were extracted from Kadsura coccinea fruit. The contents of total phenolics and anthocyanins, influences of pH and temperature on anthocyanins, and antioxidant activities of extracts were further analyzed. The results showed that the total phenolic content of peel extracts was superior to that of pulp extracts. The total anthocyanin content of peel extracts was 180 ± 2.91 mg/100 g of fresh peel tissues. K. coccinea anthocyanins were stable below pH 4, whilst high temperature and extended heating time induced their degradation. Metal-chelating capacity (MCC) assay indicated that no ortho-dihydroxy aromatic moiety existed in the B-ring of the anthocyanin molecules, but there might be a catechol group in the B-ring of the polyphenol molecules. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and reducing power of extracts decreased in the following order: peel polyphenol extracts > anthocyanin extracts > pulp polyphenol extracts. It would be worthwhile to introduce this rare fruit into more countries.     

The contribution of fruits and vegetables to dietary intake of polyphenols and antioxidant capacity in a Mexican rural diet: Importance of fruit and vegetable variety

There is mounting evidence of the health-protective role of the consumption of fruits and vegetables, which are the major contributors to dietary polyphenol intake. Lack of knowledge about the consumption of phytochemicals in the Mexican diet makes it difficult to evaluate their health significance. The aim of this study was therefore to estimate the contribution of fruit and vegetable consumption to dietary polyphenol intake and dietary antioxidant capacity in a rural population in Mexico. Despite a low intake of fruits and vegetables (< 400 g/day) in the Mexican rural diet, the mean daily intake of dietary polyphenols (> 800 mg/day) and dietary antioxidant capacity (1000-2000 ??mol trolox equivalents/day) from fruits and vegetables was similar to those determined in the Spanish Mediterranean diet. Local fruits and vegetables consumed in the Mexican rural diet are rich in polyphenols with antioxidant properties and are important source of bioactive compounds and dietary fibers. Fruit and vegetable intake needs to be promoted and lifestyle and environmental factors enhanced to improve the health status of obese Mexican rural populations.     

Comparison of phytochemical profiles,cellular antioxidant and anti-proliferative activities in five varieties of wampee (Clausena lansium) fruits

Wampee (Clausena lansium) fruit is a seasonal food containing high levels of bioactive phytochemicals which may be useful for health benefits. This study compared the phytochemical composition, total and cellular antioxidant activities (CAA) as well as anti-proliferative activities of five different varieties of wampee fruits. The results showed that six phytochemical compounds (vanillic acid, ferulic acid, rutin, syringin, catechin and hesperetin) were found in wampee fruits. Total antioxidant activities varied dramatically in these five varieties when measured with oxygen radical absorbance capacity assay and peroxyl radical scavenging capacity assay. The results also showed that wampee fruit extracts varied enormously in their CAA and exhibited significant anti-proliferative activities against HepG2 human liver cancer cells. These results suggest the potential of wampee fruits as functional foods and industrial application of wampee fruit in the future.     

Enhanced selenium content in buckwheat (<Emphasis Type="Italic">Fagopyrum esculentum</Emphasis> Moench) and pumpkin (<Emphasis Type="Italic">Cucurbita pepo</Emphasis> L.) seeds by foliar fertilisation

The fruit and thin-husked seeds of the pumpkin (Cucurbita pepo L.) and buckwheat grain (Fagopyrum esculentum Moench), both grown in Slovenia, were analysed for selenium (Se) content following foliar application of Se(VI) solution during the period of blooming. Samples were digested by a H₂SO₄-HNO₃-H₂O₂-V₂O₅ mixture and Se determined, based on hydride generation atomic fluorescence spectrometry. The whole procedure from weighing to measuring was carried out in the same Teflon vessel. The detection limit of the method was 0.14 ng g^–1 solution. Buckwheat seeds from untreated plants contained 47 ng g^–1 of Se and 394 ng g^–1 from plants after foliar fertilisation with Se. Pumpkin seeds from untreated plants contained 108 ng g^–1 of Se, and 381 ng g^–1 of Se from Se-treated plants, all per lyophilised sample. Se content in lyophilised pumpkin fruit was 15 ng g^–1 in untreated plants and 20 ng g^–1 in Se-treated pumpkin plants. It is thus feasible to enhance Se content in buckwheat and pumpkin seeds by foliar fertilisation, making them a rich source of dietary Se and useful as a raw material for enriched food products.     

Kinetics of quality changes of pumpkin (Curcurbita maxima L.) stored under isothermal and non-isothermal frozen conditions

The effects of freezing process and frozen storage at isothermal (−7, −15 and −25 °C) and non-isothermal (accelerated life testing with step-stress methodology; temperature range from −30 to −5 °C) conditions on pumpkin quality were investigated. Storage temperature conditions were selected to embrace the limits practiced in the cold chain. Quality changes, such as texture, colour CIE Lab and vitamin C (ascorbic acid) content, were evaluated for both frozen storage regimes. The freezing process (that included a pre-blanching step) and subsequent frozen storage had significant impacts on all quality parameters analysed.A fractional conversion kinetic model was adequate in colour, texture and vitamin C data fits. The storage temperature effect was successfully described by the Arrhenius law.This study shows that non-isothermal frozen storage has a marked effect on pumpkin quality.     

Physicochemical characteristics,proximate analysis and mineral composition of ostrich meat as influenced by muscle

The influence of muscle on the physicochemical characteristics, proximate analysis, and mineral composition of meat from 10 ostriches (10–12 months old), slaughtered according to commercial abattoir procedures, were evaluated. Muscle had no influence (p > 0.05) on L*-values (32.5), a*-values (11.9), water-holding capacity (11.9%), final pH (pH₂₄) values (6.07), and ash contents (1.12 g/100 g edible meat). However, intramuscular lipid contents varied (p < 0.05) from 0.88 (M. fibularis longus) to 1.44 (M. flexor cruris lateralis) g/100 g edible meat, at a mean value of 1.16 g/100 g edible meat for 10 different muscles. Sodium (34.7 mg/100 g edible meat) and iron (3.14 mg/100 g edible meat) contents, both influenced (p < 0.05) by muscle, possessed substantially lower and higher values, respectively, than values reported for beef and chicken.     

Optimization of enzymatic hydrolysis of immature citrus (Citrus unshiu Marcov.) for flavonoid content and antioxidant activity using a response surface methodology

Food Science and Biotechnology - Immature citrus with peel was enzymatically treated for production of a hydrolysate with enriched bioactive components and higher antioxidant activity. The effects...     

Anthocyanins profile,total phenolics and antioxidant activity of black currant ethanolic extracts as influenced by genotype and ethanol concentration

Ethanolic extracts prepared from the fruits of three cultivars of black currant (‘Record’, ‘Blackdown’ and ‘Ronix’) macerated in three concentrations (40%, 60% and 96%) of aqueous ethanol were investigated for their anthocyanins profile, total phenolics and antioxidant activity.     

Identification of antioxidant components and fatty acid profiles of the leaves and fruits from Averrhoa carambola

The antioxidant compounds of leaves and fruits from Averrhoa carambola were extracted with acetone:water (7:3, v/v) and distilled water. The acetone:water extracts (AWE) were separated into five different subfractions, three obtained by liquid–liquid extraction using n-hexane (HF), ethyl acetate (EAF) and water (WF), and the other two obtained by further fractionation of the WF on a Sephadex LH-20 column (WS1 and WS2). The antioxidant activities, total phenolics and total flavonoids of these extracts and fractions were investigated. Results showed that all the extracts and fractions possessed potent antioxidant activities, as measured by DPPH, ABTS and FRAP methods, with the strongest for WS2 fractions accompanied with the highest total phenolics and total flavonoids. Reversed-phase HPLC, normal-phase HPLC, MALDI-TOF-MS and ¹³C NMR analyses identified that the main antioxidant components present in WS2 fractions were essentially of procyanidin-type proanthocyanidins, consisting mainly of epicatechin units linked by B-type interflavan bonds. In addition, GC–MS analysis revealed that the most abundant fatty acids were α-linolenic acid (62.04 ± 1.65%) for leaves and oleic acid (55.44 ± 1.37%) for fruits. The amount of total unsaturated fatty acids in leaves and fruits comprised more than 77% of total fatty acid.