Chemical,physico-chemical and functional properties of pomegranate (Punica granatum L.) bagasses powder co-product

The aim of this work was to determine the chemical, physico-chemical and functional properties of pomegranate juice extraction bagasses, which were obtained in two different ways: (i) direct extraction that involved arils and peel (WFB) and (ii) only from arils (AB). The proximate composition analysis showed higher protein, fat and ash content in AB samples (p < 0.05) than WFB. However total dietary fibre, insoluble dietary fibre and soluble dietary fibre content is higher in WFB samples (50.3, 30.4 and 19.9 g/100 g d.w. respectively) than AB samples (45.6, 29.0 and 16.6 g/100 g d.w.). AB showed a pH of 4.40 while WFB showed a pH of 4.5. AB and WFB exhibited a water holding capacity of 4.5 and 4.9 g water/g d.w. respectively while the oil holding capacity was 5.9 g oil/g d.w. for AB sample and 5.9 g oil/g d.w. for WFB. Pomegranate bagasses powder co-products may be considered a potential functional ingredient in food products.     

Anthocyanins and polyphenol oxidase from dried arils of pomegranate (Punica granatum L.)

Anthocyanins are natural pigments responsible for red, purple, and blue colouration in plants. Human consumption of anthocyanins is increasing because of the rising awareness and interest in their potential health benefits. Pomegranate is one of the major sources of polyphenolic phytochemicals, such as anthocyanins. Dried pomegranate raisins (anardana) are consumed in large quantities in Asian countries, and contain substantial amounts of anthocyanins. Five anthocyanins were found to be present in pomegranate raisins. Drying adversely affected the amount of anthocyanins, with polyphenol oxidase (PPO) playing a possible role in oxidative degradation of anthocyanins. Anthocyanins are heat-stable compounds, and inactivation of PPO by processing at high temperature for short periods may prevent PPO-catalysed anthocyanin oxidation in pomegranate arils. Pomegranate PPO kinetics were partially characterised by investigating the effect of substrate (catechol) concentration; optimum pH for PPO activity was found to be 6.0.     

Brix degree and sorbitol/xylitol level of authentic pomegranate (Punica granatum) juice

With regard to 45 pomegranate fruits from different regions and several domestic varieties, fruit weight was found to be 137.1–738.2 g, peel share 34.4–73.1%, aril share 26.9–65.6% and fruit juice yield 19.2–48.0%. Brix degree of pomegranate juice samples obtained from the aforementioned fruits changed from 12.2 to 17.8 and was lower than 14.0 in approximately 18% of the samples. Titratable acidity of pomegranate juice samples varied between 2.4 and 30 g/L and the formol number varied between 4.0 and 20.0. The sorbitol/xylitol content ranged between 16 and 423 mg/L, mostly lying between 51 and 200 mg/L with a frequency of 64%. The share of samples containing sorbitol/xylitol higher than 250 g/L is 7%.     

Supercritical CO2 extraction optimization of pomegranate (Punica granatum L.) seed oil using response surface methodology

This study examined extraction of pomegranate seed oil by using supercritical carbon dioxide. Response surface methodology was used to evaluate the effects of the process parameters, namely extraction pressure, temperature and CO₂ flow rate on the yield of pomegranate seed oil. The extraction parameters were optimized with a central composite design experiment. The linear term of pressure, followed by the linear term of CO₂ flow rate, the quadratic terms of pressure, temperature and CO₂ flow rate and the interactions between pressure and temperature, as well as CO₂ flow rate and temperature, had significant effects on the oil yield (p < 0.05). Maximum yield of pomegranate seed oil from the mathematical model was predicted to be 156.3 g/kg dry basis under the condition of pressure 37.9 MPa and temperature 47.0 °C with CO₂ flow rate of 21.3 L/h. The fatty acid composition and the tocopherols' content of pomegranate seed oil extracted using supercritical CO₂ were compared with those obtained by Soxhlet method. Minor difference was found in the fatty acid composition of the oils extracted by the two methods. The content of total tocopherols was about 14% higher in the oil extracted with supercritical CO₂ than that obtained by Soxhlet extraction.     

Identification of phenolic compounds from pomegranate (Punica granatum L.) seed residues and investigation into their antioxidant capacities by HPLC-ABTS assay

In this study, phenolic compounds were extracted and isolated from pomegranate seed residue (PSR). Phytochemicals and antioxidant capacity of extracts from PSR were firstly investigated. Total phenolic (TP) and proanthocyanidin (PC) contents of the extracts were determined as 2427.90 and 505.63 mg catechin equivalent of 100 g dry weight respectively. To evaluate the antioxidant capacity of individual compounds, on line assay of coupling high performance liquid chromatographic separation with ABTS free radical reaction system (HPLC-ABTS⁺) was carried out. 17 compounds in PSR extracts were detected with antioxidant capacity, and HPLC associated with electrospray ionization mass spectrometry (HPLC-ESI-MS) was used to identify them. The main phenolics in PSR identified were flavol-3-ols, phenolic acids, flavonoid glycosides, and hydrolysable tannin. The results showed that PSR contained some amount of antioxidant compounds, and the HPLC-ABTS⁺ on line method was fast, sensitive and effective.     

Effects of storage temperature and duration on chemical properties,proximate composition and selected bioactive components of pomegranate (Punica granatum L.) arils

Effects of storage temperature on nutritional composition of pomegranate cultivars (‘Arakta’, ‘Bahgwa’ and ‘Ruby’) were investigated. Pomegranate arils were stored at 1, 4, and 8 °C at 95% relative humidity for 14 days. Arils stored at 1 °C were removed from storage after 14 days and kept at ambient conditions for one day. Anthocyanins, ascorbic acid and proximate composition were measured on day 0, 7, 14 and 15. O₂ consumption and CO₂ production increased at elevated temperatures. Proximate composition of pomegranate arils was similar amongst cvs.: 0.8 g/g moisture, 5.2 g kg⁻¹ ash, 13–15 g kg⁻¹ fat, 27–29 g kg⁻¹ dietary fibre, 11–12 g kg⁻¹ protein, 140–150 g kg⁻¹ carbohydrate and 310–320 kJ 100 g⁻¹ energy. ‘Arakta’ had highest titratable acidity (TA) level (0.3 ± 0.01 g 100 mL⁻¹) and ascorbic acid (26.0 ± 1.3 mg kg⁻¹). Low β-carotene levels (1.7–3.5 mg kg⁻¹) were detected in all samples. Nutritional composition of arils was not significantly affected at 1 and 4 °C for 14 d. Temperature did not affect total soluble solids (TSS), but increased TA and reduced TSS/TA. No mould growth was observed in arils stored at 1 °C after 14 d.     

Analysis of free and bound aroma compounds of pomegranate (Punica granatum L.)

Volatile aroma compounds were isolated from pomegranate arils by high vacuum distillation (HVD) and solvent extraction with diethyl ether. The HVD distillate exhibited a fresh-fruity and characteristic pomegranate aroma while the total ether extract was devoid of this note in its concentrate. Gas chromatography–mass spectroscopy (GC–MS) analysis revealed the presence of 3-octen-1-yl acetate, trans-3-hexen-1-ol, hexanol and 2-methyl pentanol only in the high vacuum distillate. Ether extract was dominated by 2-heptanol, 2-nonanol and 3-methyl-2-butanol. Based on olfactometric analysis of the HVD isolate, 3-octen-1-yl acetate was identified as the key odorant of pomegranate. Chemical synthesis of this compound, further confirmed its structure. Among the bound aroma compounds, 2-phenylethanol (40%), alpha-terpineol (4.53%) and 2-heptanol (6.35%) were identified as the major compounds existing as glycoconjugates. Identification of the character impact compound and the occurrence of glycosidic precursors in pomegranate are being reported here for the first time.     

Optimisation of accelerated solvent extraction of antioxidant compounds from rosemary (Rosmarinus officinalis L.), marjoram (Origanum majorana L.) and oregano (Origanum vulgare L.) using response surface methodology

The present study optimised the accelerated solvent extraction (ASE) conditions (Dionex ASE® 200, USA) to maximise the antioxidant capacity of the extracts from three spices of Lamiaceae family; rosemary, oregano and marjoram. Optimised conditions with regard to extraction temperature (66–129 °C) and solvent concentration (32–88% methanol) were identified using response surface methodology (RSM). For all three spices results showed that 129 °C was the optimum temperature in order to obtain extracts with high antioxidant activity. Optimal methanol concentrations with respect to the antioxidant activity of rosemary and marjoram extracts were 56% and 57% respectively. Oregano showed a different response to the effect of methanol concentration and was optimally extracted at 33%. The antioxidant activity yields of the optimal ASE extracts were significantly (p < 0.05) higher than solid/liquid extracts. The predicted models were highly significant (p < 0.05) for both total phenol (TP) and ferric reducing antioxidant property (FRAP) values in all the spices with high regression coefficients (R²) ranging from 0.952 to 0.999.     

A novel thermostable chitinase (PJC) from pomegranate (Punica granatum) juice

A novel chitinase was isolated and purified to its homogeneity from pomegranate juice by a combination of ammonium sulphate precipitation and ion-exchange chromatography. The pomegranate juice chitinase (PJC) was purified to specific activity of 14.5 U/mg and a recovery of 34%. The monomeric protein migrated on SDS–PAGE at 29 kDa. The enzyme was found to be glycosylated (7.2%). It exhibited optimal activity at pH 4.5 and 70 °C. The enzyme was stable in the pH range 3.0–9.0 and up to 65 °C. The internal peptide sequence results suggest that the purified PJC shared high homology with class III chitinases of other known plant chitinases. The purified enzyme could hydrolyse colloidal chitin to its oligomers. It did not exhibit any antifungal activity.     

Protective role of Punica granatum (pomegranate) peel and seed oil extracts on diethylnitrosamine and phenobarbital-induced hepatic injury in male rats

The present study is an attempt to reveal the protective role of Punica granatum peel and seed oil extracts against diethylnitrosamine (DEN) and phenobarbital (PB) induced hepatic injury in rats. DEN administration increased the levels of malondialdehyde (MDA), DNA fragmentation, caspase-3 and glutathione reductase (GSR) activities, while the level of reduced glutathione (GSH) and the activities of superoxide dismutase (SOD), glutathione S-transferase (GST) and total glutathione peroxidase (t-GPx) were decreased compared with the control. Treatment with peel and seed oil extracts pre, during and post DEN administration improved liver functions, decreased the levels of MDA, DNA fragmentation, caspase-3 and GSR activities with an elevation in levels of GSH, SOD, GST and t-GPx activities. This indicates that these extracts reduced the oxidative stress and apoptosis induced by DEN. Also the effect of administration of PE and SOE separately for a long time (23 weeks) on healthy rats was studied.     

Identification of steroid hormones in pomegranate (Punica granatum) using HPLC and GC–mass spectrometry

Although it has been known that pomegranate (Punica granatum L.) contains several steroid hormones, concrete experimental proofs about that have not been published until now. In order to identify and evaluate the contents of steroid hormones including estrone in pomegranate, we analyzed pomegranate seed, fruit juice and commercial preparations. We developed a reproducible and sensitive method for separation and identification of steroid hormones in pomegranate samples using both high performance liquid chromatography (HPLC)–PDA and gas chromatography (GC)–MS. In case of HPLC, an isocratic elution method using 35% aqueous acetonitrile solution at 1.0 ml/min with photodiode-array (PDA) detection at 225 nm and 254 nm was found to optimally separate and identify the steroid hormones from the pomegranate samples with a run time of less than 30 min. The pomegranate samples were comparatively analyzed to the HPLC results by GC/FID or GC/MS detection on a HP-1 (30 m length, 0.32 mm I.D.) with helium as carrier gas under the oven temperature control as follows: start 220 °C for 5 min, raising 5 °C per min, final 280 °C for 10 min. The HPLC and GC methods were successfully applied to the identification of steroid hormones in pomegranate samples. Our results suggested that there were no steroid estrogens including estrone, estradiol and testosterone in pomegranate seed, fruit juice and preparations. Consequently, we assumed that the previously reported analysts of pomegranate were misunderstood their analytical results according to either the estrogen-like effects or similarity of peak retention time and Rf values in experiments.     

Anthocyanin and colour changes during processing of pomegranate (Punica granatum L., cv. Hicaznar) juice from sacs and whole fruit

The effects of clarification and pasteurisation on anthocyanins (ACNs) and the colour of pomegranate juice (PJ) produced from sacs and whole fruits were investigated. Clarification caused a loss of 4% of ACNs in juice from sacs (JFS) and a loss of 19% in juice from whole fruit (JFWF). After pasteurisation, there was an 8–14% and 13–9% loss of ACNs from unclarified and clarified JFS and JFWF samples, respectively. Polymeric colour was very high even in unclarified samples (25–29%). Compared to JFS, higher polymeric colour was formed in JFWF. HPLC analyses of PJ revealed that cyanidin-3,5-diglucoside was the major ACN, followed by cyanidin-3-glucoside and delphinidin-3-glucoside. Cyanidin-3,5-diglucoside showed higher stability to clarification and pasteurisation than cyanidin-3-glucoside in both PJ samples. Cold clarification with only gelatin is recommended for PJ. To prevent excessive ACN loss and the formation of brown colouring, PJ should be subjected to minimal heating.     

Antioxidant capacity and anthocyanin profile of sour cherry (Prunus cerasus L.) juice

The antioxidant capacities, total polyphenolic content and monomeric anthocyanin content of eleven types of sour cherry juice obtained from different varieties of sour cherries were investigated. Antioxidant capacity, total polyphenolic content and monomeric anthocyanin contents of the juices were within the ranges 20.0–37.9 mmol/L, 1510–2550 and 350.0–633.5 mg/L, respectively. The main anthocyanin compound in sour cherry juice was cyanidin-3-glucosylrutinoside at concentrations between 140.3 and 320.9 mg/L. Cyanidin-3-glucosylrutinoside was followed by cyanidin-3-rutinoside within a concentration range of 25.5–85.5 mg/L. Cyanidin-3-sophoroside and cyanidin-3-glucoside contents were relatively low (2.6–21.5 and 2.0–9.9 mg/L). Anthocyanin capacity and total polyphenol content were fairly well correlated (r = 0.742, p < 0.01), whereas the correlation between antioxidant capacity and monomeric anthocyanin content was insignificant (r = 0.423, p > 0.05). The correlation between antioxidant capacity – cya-3-glucosylrutinoside (r = 0.606, p < 0.01) and antioxidant capacity – cya-3-rutinoside (r = 0.628, p < 0.01) was significant.     

Quality and antioxidant properties of bread containing turmeric (Curcuma longa L.) cultivated in South Korea

Turmeric (Curcuma longa L.) powder was used to substitute 0%, 2%, 4%, 6% and 8% of wheat flour for making turmeric wheat breads. Proximate composition, physical quality, functional components (curcumin and total phenols) and antioxidant properties of breads containing turmeric were analysed and compared with those of wheat bread. Hardness, crumb colour a and b values, curcumin content and total phenolic contents of breads significantly increased with the addition of turmeric powder. Water activity, specific volume and crumb colour L value of breads decreased with the addition of turmeric powder. Breads containing turmeric powder also showed good antioxidant activity as tested by the β-carotene-linoleate bleaching assay. A 4% substitution of wheat flour with turmeric powder showed acceptable sensory scores which were comparable to wheat bread. Breads containing turmeric powder can thus be developed as a health-promoting functional food.     

Preliminary characterisation of cornelian cherry (Cornusmas L.) genotypes for their physico-chemical properties

Fruit weight, antioxidant capacity, total anthocyanins, total phenolics, ascorbic acid, soluble solid content (SSC), reducing sugar and acidity of a number of selected cornelian cherry (Cornusmas L.) genotypes of varied pigmentation were investigated. Two methods, namely β-carotene bleaching and ferric reducing antioxidant power (FRAP) were used to determine total antioxidant capacity, while Folin–Ciocalteu reagent was used to determine total phenols. Fruit weight, SSC and ascorbic acid content of genotypes were 2.09–9.17; 12.53–21.17% and 29–112 mg/100 g, respectively. Antioxidant activity and total phenolic content varied among genotypes and 44-18 genotype had the highest antioxidant capacity using both methods. This genotype also had the highest total phenolic (74.8 mg GAE/g DW) and total anthocyanin (115 mg cyanidin-3-glucoside equivalents /100 g FW) content. There are linear relationships between antioxidant capacities and total phenols. The present study demonstrates the potential of certain cornelian cherry genotypes, notably 44-18, for improvement of nutritional value through germplasm enhancement programmes.     

Free-radical-scavenging activity and total phenols of noni (Morinda citrifolia L.) juice and powder in processing and storage

The fresh juice of noni (Morinda citrifolia L.), a tropical plant used as a folk medicine in Pacific islands, possessed free-radical-scavenging activity (RSA), 1,1-diphenyl-2-picrylhydrazyl (DPPH), at 140 mg equivalent ascorbic acid/100 ml and total phenols at 210 mg gallic acid/100 ml. Fermentation of noni fruit for 3 months resulted in a loss of more than 90% of RSA. Dehydration at 50 °C produced a loss of 20% of RSA. Storage of fresh noni juice at 24 °C for 3 months reduced RSA more than 90%. Storage of noni juice or powder at −18 °C and 4 °C for 3 months decreased RSA by 10–55%. The reduction of RSA of noni juice or purée during heat treatment or dehydration was much greater than reduction of total phenols. For maintenance of the substantial antioxidant properties of noni products, processing of noni powder or fresh frozen noni juice rather than fermented noni juice is recommended.     

Changes in anthocyanins in arils of chitosan-coated pomegranate (Punica granatum L. cv. Rabbab-e-Neyriz) fruit during cold storage

Edible coatings as chitosan treatments (0%, 1% and 2%) were applied to ‘Rabbab-e-Neyriz’ pomegranate (Punica granatum L.). The effect of chitosan coating on individual anthocyanins and colour parameters of the juice during storage at 2 °C or 5 °C was examined. Six predominant anthocyanins were identified in the juice, with up to 935 mg/L total anthocyanins at the time of harvest. Cyanidin 3,5-diglucoside (402 mg/L) was the major pigment. The total anthocyanin content and chroma decreased with storage time in all applied treatments, although lightness and hue angle increased. These changes were reduced with chitosan treatments and at lower storage temperature (2 °C as compared to 5 °C). Based on the obtained results, the diglucoside anthocyanins were more stable than the monoglucosides. Chitosan coating followed by cold storage delayed anthocyanin degradation and prevented colour deterioration in the pomegranate arils.     

Antioxidant constituents in some sweet pepper (Capsicum annuum L.) genotypes during maturity

Changes in total phenolics, antioxidant activity (AOX), carotenoids, capsaicin and ascorbic acid were monitored during three maturity stages in 10 genotypes of sweet pepper. In an attempt to explain the variations during maturity stages (green, intermediate and red/yellow), the data was expressed both on fresh and dry weight basis. All the antioxidant constituents (phenolics, ascorbic acid and carotenoids) and AOX, when expressed on fresh weight basis in general, showed an overall increasing trend during maturity in all the genotypes studied. On dry weight basis, phenolic content declined in majority of the genotypes during maturity to red stage. This decline was significant (P<0.05) in Parker, Torkel, HA-1038 and Flamingo. Genotype Flamingo and Golden Summer had the highest phenolic content of 852.0 mg 100 g⁻¹ and 720.5 mg 100 g⁻¹, at their final red and yellow maturity stages, respectively. With maturation, most of the cultivars showed a declining trend with regard to capsaicin content while total carotenoids and β-carotene content increased significantly. Anupam was a promising genotype in terms of both total carotenoids and β-carotene content. Ascorbic acid content declined progressively with advancing maturity. Genotype HA-1038 had the maximum content (3030 mg 100 g⁻¹ dwb) at the green stage. AOX in general, increased with maturity and registered a 1.30-1.95fold increase from green to red stage.The study proposes the nutritional significance of consuming sweet peppers at the red maturity stage because of enhanced functional properties. Overall genotype Flamingo and Anupam represent superior genotypes for both nutrition and germplasm improvement.     

Antioxidant activity of microwave-assisted extract of Buddleia officinalis and its major active component

Buddleia officinalis Maxim, commonly used as rice dye for festivals, was extracted with ethanol using microwave-assisted extraction and Soxhlet extraction. The antioxidant activities of microwave-assisted extract of B. officialis (MEB) and Soxhlet extract of B. officianils (SEB) at the optimum extraction conditions were evaluated and compared with synthetic antioxidant butylated hydroxytoluene (BHT) employing DPPH free radical assay, ABTS assay, total antioxidant activity and reducing power. MEB and SEB had stronger antioxidant activities than BHT in all assays except reducing power, and the effects decreased as follows: MEB > SEB > BHT. The total phenolic contents of MEB and SEB reached 113.56 mg/g and 100.94 mg/g dry weight of extract, respectively, expressed as pyrocatechol equivalents, while the total flavonoids contents were 75.33 mg/g and 62.56 mg/g dry weight of extract, respectively, expressed as catechin equivalents (P < 0.05). Higher phenolic and flavonoids compounds may be major contributors to their higher antioxidant activities. Following activity-oriented separation, luteolin was isolated as an active principle, which exhibited excellent free radical scavenging activities with DPPH IC₅₀ 3.09 μg/ml and ABTS IC₅₀ 2.20 μg/ml.     

Quantification of phenolic contents and antioxidant capacity of Atlantic sea cucumber, Cucumaria frondosa

The antioxidant activity (oxygen radical absorbance capacity, ORAC) and total phenols and flavonoids were determined in extracts from digestive tract, gonads, muscles and respiratory apparatus of sea cucumber, Cucumaria frondosa. Total phenols content varied from 22.5 to 236.0 mg of gallic acid equivalents/100 g dw, and flavonoids from 2.9 to 59.8 mg of rutin equivalents/100 g. ORAC values ranged from 140 to 800 μmol of Trolox equivalents/g dw. Among all extracts, best antioxidant potencies were observed in ethyl acetate extracts from digestive tract, and in acetonitrile-rich fractions obtained from mixed extracts using acetonitrile/TFA (trifluoroacetic acid) acidified water on muscles, gonads and respiratory apparatus. The weakest potencies were observed with water extracts from digestive tract and respiratory apparatus, and with water-rich fractions obtained from mixed extraction of gonads and muscles. A significant correlation was observed between ORAC values and total phenol content in extracts and fractions of gonads and muscles, but ORAC and phenols were not correlated in digestive tract and respiratory apparatus extracts. ORAC values were significantly correlated (p < 0.05) with total flavonoids in all extracts. Successive eluates obtained from solid-phase extraction of water-rich fractions using C₁₈ cartridge showed ORAC values (105–500 μmol of TE/g) reaching up to 2.3 times the potency of their parent fractions. Flavonoids are suggested to be mainly responsible for observed activities. Our results provide a first quantitative evaluation of C. frondosa tissues as useful sources of antioxidants for human consumption.