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.     

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.     

Extraction modeling and activities of antioxidants from pomegranate marc

To develop value-added antioxidants from the peel and seeds of pomegranate marc, a by-product after pomegranate juice processing, the effects of drying before extraction and processing parameters on the extraction kinetics and product properties were systematically studied using water as an environmental friendly solvent for the extraction. The results showed that the drying process did not significantly affect the yield, content, and activity of antioxidants from either the peel or seeds. The antioxidants extracted from the peel had higher yield and content than those from the seeds. The yield and content of antioxidants increased with reduced particle size and increased water/sample ratio and temperature, but antioxidant activity was low when extraction temperature was high. By considering the antioxidant activity and operation cost, the recommended extraction conditions were peel particle size of 0.2 mm, water/peel ratio of 50/1 (w/w), temperature of 25 °C, and extraction time of 2 min, which gave the high antioxidant yield (11.5%) and content (22.9%), and DPPH scavenging activity of 6.2 g/g. Kinetic models were successfully developed for describing the extraction processes with different processing parameters.     

Comparison of antioxidant activities of juice, peel, and seed of pomegranate (Punica granatum L.) and inter-relationships with total phenolic, Tannin, anthocyanin, and flavonoid contents

In this study, the antioxidant activities of juice, peel, and seed parts of pomegranate were investigated by using DPPH scavenging activity, β-carotene bleaching method, reducing power, and metal chelating activity. Sample of pomegranates which are named Punica granatum L. cv. Hicaznar, genotype 19–121, genotype 17–67, and genotype 19–66 obtained from BATEM (West Mediterranean Agricultural Research Institute) in Anlalya. The EC₅₀ values of DPPH scavenging activities in peel extracts (PE) had 23.4-fold higher than the juice extracts (JE), and the seed extracts (SE) had 2.3-fold higher than JE. The reducing power in peel extracts was found to be 4.7-fold higher than SE and 10.5-fold higher than the JE. The highest metal chelating capacity (37.22%) was determined in peel, while the lowest (7.151%) in seed. Generally, in peel, the total polyphenol, flavonoid, tannin contents, and in juice, the total polyphenol, anthocyanin, tannin contents, and acidity significantly affected to antioxidant activities.     

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.     

Approaches to understanding the contribution of anthocyanins to the antioxidant capacity of pasteurized pomegranate juices

Influence of processing and storage conditions on anthocyanin stability and antioxidant activity of clarified and cloudy juices from arils of the ‘Mollar’ pomegranate variety was studied. Clarification process reduced the content of total monomeric and individual anthocyanins, and increased the antioxidant activity of pomegranate juice. Thermal treatments (65 and 90 °C for 30 or 5 s) decreased the percentage of polymeric anthocyanin form, increasing on the contrary the monomeric one. In any case, storage temperature was the main factor affecting all the parameters tested. Cyanidin 3-O-glucoside (Cy3G) was more instable than delphinidin 3,5-di (Dp3,5dG) and cyaniding 3,5-diglucosides (Cy3,5dG). A linear relationship was observed between oxygen radical absorbance capacity (ORAC) and total monomeric anthocyanins, suggesting that they contributed strongly to the antioxidant capacity. Results presented in this study show that hurdle technology (heating plus refrigeration) may help to reduce anthocyanin degradation in pasteurized pomegranate juice, avoiding a dramatic impact on its colour and preserving the beneficial effects of this specific bioactive compounds on human health.     

浓缩石榴汁流变特性研究

研究了不同浓度的石榴汁在不同温度下的流变特性。结果表明:在实验范围内,石榴汁表现为胀塑性流体,通过回归分析,温度对表观粘度的影响可以用Arrhenius方程表示,浓度对表观粘度的影响可以用指数方程更好地表示,并推导出温度和浓度对表观粘度综合影响的方程式。该方程的建立可以用来预测实际加工过程中一定温度和浓度时石榴汁的表观粘度。     

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%.     

Effects of pomegranate sauce on quality of marinated anchovy during refrigerated storage

Effects of pomegranate sauce on the quality of marinated anchovy during storage at 4 °C were investigated. Anchovy were marinated with 30 g/L acetic acid and 150 g/L salt, put into glass jars, filled with either sunflower oil or pomegranate sauce and stored at 4 °C. Total volatile basic nitrogen (TVB-N) and trimethylamine (TMA-N) values increased during the storage. Higher values for free fatty acid (FFA), conjugated diens (k-dien) and para-anisidine (p-Av) were found in samples with sunflower oil than those with pomegranate sauce. Samples in pomegranate sauce showed better oxidative stability. Higher taste and flavour and lower appearance scores were found for samples in pomegranate sauce than those samples in sunflower oil. It was found that pomegranate sauce was as least effective as the traditional sunflower oil to keep quality. Pomegranate sauce also produced desirable taste and flavour but the coloration should be studied in further studies.     

Physico-chemical characteristics of juice extracted by blender and mechanical press from pomegranate cultivars grown in Georgia

Pomegranate juice is consumed widely for its possible health benefits. The aril juice from 15 pomegranate cultivars grown in Georgia were analysed for juice yield based on fresh weight (FW) and physico-chemical properties, using blender and mechanical press extraction. Blender had a higher juice yield (42.04% FW) compared to mechanical press (38.05% FW). Total phenolics and antioxidant capacity was determined by Folin–Ciocalteau method and ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC) assays, respectively. Total monomeric anthocyanins were determined by pH differential method and RP-HPLC. The major anthocyanin was delphinidin 3-glucoside. High negative and significant (p ? 0.05) correlations were found between pH and titratable acidity (TA). The total soluble solids content (TSS) averaged 15.59 in blender and 14.94 °Brix in mechanical press. Chemical analysis of juice showed significant differences among cultivars and extraction methods. Overall, blender was more efficient than mechanical press juice extraction.     

Antioxidant properties of pomegranate (Punica granatum L.) bagasses obtained as co-product in the juice extraction

The aim of this work was to determine the total phenol (TPC), the total flavonoid (TFC), the tannins contents (TC), organic acids and sugar contents and the antioxidant activity 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). Four different test systems were used, namely the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, the ferric reducing antioxidant power (FRAP); determination of antioxidant activity with thiobarbituric acid reactive species (TBARS) and the ferrous ion-chelating ability (FIC). WFB presented higher total phenolic, flavonoid and tannins contents (10.05 mg gallic acid equivalent/g sample; 7.19 mg rutin equivalent/g sample and 8.18 mg catechin/g sample) than AB. The organic acid detected were oxalic acid, citric acid, malic acid and succinic acid while the sugar identified were fructose and glucose. As regards antioxidant activity, at all concentrations and with all methods, the WFB samples showed a higher antioxidant activity than AB samples. BHT, used as control positive, present higher antioxidant activity than WFB and AB in all antioxidant methods used except in the FRAP assay.The results of this study indicate that pomegranate bagasse obtained as co-product in the process to obtain juice may be considered a good source of natural compounds with significant antioxidant activity which could be suitable for applications on the food industry as potential ingredient for food products.     

The effect of ultrasound waves on the efficiency of membrane clarification of pomegranate juice

Pomegranate juice has a turbid appearance, which poses difficulties in its concentration process. Membrane clarification can be used to clarify pomegranate juice; however, membrane fouling reduces the permeate flux, limiting its effectiveness. Ultrasound at 30 kHz was used to reduce membrane fouling. Results were compared with the data obtained for membrane clarification without ultrasonic treatment at the same temperature. Results showed that permeate flux increased with ultrasonic treatment. Evaluation of different membrane fouling characteristics showed that the total membrane resistance fell due to the reduction in irreversible fouling and cake resistance. However, ultrasound did not affect the thick caking produced in membrane processing at low feed‐flow rates. Evaluation of the physicochemical properties of pomegranate juice showed that ultrasound can decrease antioxidant activity due to the reduction in total anthocyanin content. Also, total soluble solid content and acidity of pomegranate juice changed with ultrasonic treatment.     

Spray-drying microencapsulation of pomegranate juice increases its antioxidant activity after in vitro digestion

Most of the work on pomegranate antioxidant and antibacterial activity has been carried out with solvent extracts of different plant or fruit parts. Biosensitive compounds in juice may be subject to oxidation, reducing their biological activities. Microencapsulation can be used to protect compounds, allowing its incorporation into functional foods. This study aimed at investigating antioxidant activity after in vitro digestion of microencapsulated juice. Pomegranate juice was encapsulated by spray drying its maltodextrin and gum arabic. The average diameter of the microcapsules was 10–50 µm. We evaluated the bioaccessibility of microencapsulated phenolic compounds by using an in vitro enzymatic digestion. The total phenolic content in digested microencapsulated juice was three times greater than in undigested, indicating that the compounds were made bioaccessible. Digestion also increased antioxidant activity, as measured by ABTS●+ or by DPPH●. Additionally, microencapsulated pomegranate juice showed antibacterial activity against the nine bacteria species tested.     

Total phenols and antioxidant capacity in 10 Moroccan pomegranate varieties

The study focused on characterizing the 10 major Moroccan cultivars to acknowledge the quality and bioactive compounds of the fruits. The following determinations were assessed: pomegranate fruit maturity index, which truly defines juice taste, as well as organic acids and sugar contents, total phenols, and antioxidant activity of pomegranate juice. The cultivar per se (genotype) behaved as the most influencing factor conditioning pomegranate sugar and organic acids profiles, antioxidant activity, and total phenolics. The assessment of pomegranate chemical compositions implies the great potential of Moroccan cultivars for both fresh market and fruit processing. In fact, the "Hamde" sour cv. seems particularly suitable for juice production because of its high phenolics content. Additionally, the presence of bioactive compounds in pomegranate juices may encourage their consumption for potential health benefits. PRACTICAL APPLICATION: The cultivar per se (genotype) behaved as the most influencing factor conditioning pomegranate sugar and organic acids profiles, antioxidant activity, and total phenolics. Given the divergence observed on bioactive compounds concentrations and antioxidant activity among evaluated cultivars, the genotype factor should be considered as the most influencing factor in future breeding programs to enhance the synthesis of beneficial bioactive compounds.     

Effects of feeding polyphenols from pomegranate extract on health, growth, nutrient digestion, and immunocompetence of calves

Objectives were to determine effects of feeding pomegranate extract (POMx) rich in polyphenols on performance, health, nutrient digestion, and immunocompetence of calves in the first 70 d of age. Holstein calves (n = 67), at 2 ± 1 d of age (d 0 = birth day) were randomly assigned to 0 (control), 5 (POMx5), or 10 g/d (POMx10) of pomegranate extract containing 16.9% gallic acid equivalent (GAE) to result in intakes of 0, 850 and 1,700 mg of GAE/d or an average of approximately 0, 15, and 30 mg of GAE/kg of body weight (BW) per day. All calves received colostrum during the first 24 h, pasteurized milk thereafter until 61 d of age, and grain was fed ad libitum for the first 70 d of age. Calves were housed in individual hutches, and grain intake, attitude and fecal scores, incidence and duration of health disorders, and treatments for health problems were evaluated daily. Body weight was measured on 2 consecutive days at 2, 30, and 70 d of age and averaged for each measurement. Concentrations of glucose and 3-hydroxybutyrate were measured in plasma. Nutrient digestion was measured using total fecal collection during a 3-d period. Neutrophil phagocytic and killing activities and antibody response to immunization with ovalbumin were measured. Peripheral blood mononuclear cells were cultured and cytokine production measured. Feeding POMx had no effect on intake or BW gain in the first 30 d of age, but after 30 d of age, both grain dry matter intake and BW gain decreased with increasing addition of POMx, which resulted in calves that were 1.8 and 4.3 kg lighter at 70 d of age for POMx5 and POMx10, respectively, compared with controls. Feeding POMx did not influence dry matter, organic matter, or starch digestibility, but it reduced crude protein and fat digestion. Plasma concentrations of glucose and 3-hydroxybutyrate were similar among treatments throughout the first 70 d of age. Measures of calf health such as fecal and attitude scores, risk of fever, and rectal temperature were not altered by treatments. Similarly, neutrophil phagocytic and killing activities did not differ among treatments. On the contrary, feeding POMx increased synthesis of interferon-γ and interleukin-4 by peripheral blood mononuclear cells and improved total immunoglobulin G responses to ovalbumin vaccination. These results suggest that feeding POMx top-dressed onto the grain suppresses intake of grain and digestibility of fat and protein, likely because of the high tannin content. Nevertheless, polyphenols from POMx enhanced mitogen-induced cytokine production and response to vaccination, which might benefit immune competence of calves and potentially health. Additional studies are warranted to minimize the effect of POMx on intake and digestibility and to better understand the mechanisms by which polyphenols improve immune response of calves.     

石榴果汁菊花茶饮料的研制

以安徽怀远石榴和滁州贡菊为主要原料,将所得的石榴果汁与菊花浸提液进行调配,通过正交试验,制得一种既有石榴的酸甜口味又有菊花香味的果汁茶饮料.其配方为:菊花浸提液40%、石榴果汁20%、白砂糖12%、柠檬酸0.10%.     

Anti-oxidant effect of extracts of kinnow rind,pomegranate rind and seed powders in cooked goat meat patties

To overcome the disadvantages of using synthetic anti-oxidants in meat products, an investigation was carried out to evaluate the anti-oxidant effect of extracts of fruit by-products viz., kinnow rind powder (KRP), pomegranate rind powder (PRP) and pomegranate seed powder (PSP) in goat meat patties. Total phenolics content, DPPH radical scavenging activity and effect of these extracts on instrumental color, sensory attributes and TBARS values during storage (4 ± 1 °C) of goat meat patties were evaluated. Results showed that these extracts are rich sources of phenolic compounds having free radical scavenging activity. Hunter Lab L value significantly (P < 0.05) lowered in PRP followed by PSP and KRP patties. Sensory evaluation indicated no significant differences among patties. Further, a significant (P < 0.5) reduction in TBARS values (lipid oxidation) during storage of goat meat patties was observed in PRP, PSP and KRP as compared to control patties. Average TBARS values (mg/kg meat) during refrigerated storage (4 ± 1 °C) were significantly lower in PRP, followed by PSP and KRP as compared to control. The overall anti-oxidant effect was in the order of PRP > PSP > KRP. It was concluded that extracts of above fruits by-product powders have potential to be used as natural anti-oxidants in meat products.     

石榴果肉果汁饮料工艺研究

重点研究了石榴果肉果汁及饮料的生产工艺、配方、加工技术,规定了相应的质量标准。采用适当的配方、加工工艺,能生产具有较高营养价值、果肉感强的天然石榴果肉果汁饮料。     

Effect of salt,kinnow and pomegranate fruit by-product powders on color and oxidative stability of raw ground goat meat during refrigerated storage

Effects of salt, kinnow and pomegranate fruit by-product powders on color and oxidative stability of raw ground goat meat stored at 4 ± 1 °C was evaluated. Five treatments evaluated include: control (only meat), MS (meat + 2% salt), KRP (meat + 2% salt + 2% kinnow rind powder), PRP (meat + 2% salt + 2% pomegranate rind powder) and PSP (meat + 2% salt + 2% pomegranate seed powder). Addition of salt resulted in reduction of redness scores. Lightness increased in control and unchanged in others during storage. Redness scores declined and yellowness showed inconsistent changes during storage. Thiobarbituric acid reactive substances (TBARS) values were higher (P < 0.05) in MS followed by control and KRP samples compared to PRP and PSP samples throughout storage. The PSP treated samples showed lowest TBARS values than others. Percent reduction of TBARS values was highest in PSP (443%) followed by PRP (227%) and KRP (123%). Salt accelerated the TBARS formation and by-products of kinnow and pomegranate fruits counteracted this effect. The overall antioxidant effect was in the order of PSP > PRP > KRP > control > MS. Therefore, these powders have potential to be used as natural antioxidants to minimize the auto-oxidation and salt induced lipid oxidation in raw ground goat meat.     

石榴榨汁方法及其护色工艺研究

石榴的榨汁和护色在石榴汁生产过程中是很重要的工序,直接影响出汁率和产品的品质。对石榴的榨汁和护色方法进行研究表明,剥皮压榨石榴的出汁率和品质明显高于带皮压榨石榴,复合护色剂的护色效果高于单一护色剂,复合护色剂的最佳添加量为0.4g/100g柠檬酸和0.01g/100gVc,石榴汁自然澄清最佳时间为3h。