White Guava Research Articles

Physical and chemical characterization of guava (Psidium guajava L.) genotypes grown in subtropical condition

Guava is a high-value tropical fruit that is widely grown in tropical and subtropical regions around the world. In the adaptation studies carried out in Turkey, guava was determined as the most prominent species with its cold resistance feature. The use of seedlings in cultivation created a genetic variation and differences were observed between the resulting genotypes, especially in terms of fruit size, shape and colour. Based on this observation, this study aimed to characterize 13 different guava fruit genotypes based on physical, chemical, bioactive and aroma properties. In the adaptation studies carried out in Turkey, guava was determined as the most prominent species with its cold resistance feature. There is only one commercial variety namely ‘Ruby Supreme’ grown in Turkey. Presently, the interest of the guava cultivation has been increased and farmers were used seedling material instead of vegetative to establish orchard. Due to the cross pollination, it has been observed great variation in the population. Therefore, it is important to select promising genotypes according to fruit size, shape and colour. The present study was evaluated 13 different guava genotypes according to physical, chemical, bioactive and aroma properties. Significant differences were observed among the genotypes. One genotype was found superior over all the genotypes, in terms of fruit weight (131.44 g) and length (82.00 mm). Although three genotypes were having lower values than the other samples in results of total soluble solids, they had higher results in terms of antioxidant capacity and total phenolic content. Two genotypes formed a separate group from all other genotypes in terms of (Z)-3-Hexen-1-yl acetate (sweet, pear, melon), 3-Hexenal (melon, tropical) and Ethyl alcohol (fruit and sweet) components. The flavor components are distinctive for the guava samples, as are the physical properties. It was also determined that the white guava genotypes had very different chemical and aromatic properties from other genotypes. The promising genotypes can be utilized in the future breeding programme to improve new guava varieties.

White guava (Psidium guajava L.) fruit juice ameliorated the number of spermatogenic cells in rats (Rattus Novergicus) exposed to lead acetate

White guava (Psidium guajava L.) fruit juice ameliorated the number of spermatogenic cells in rats (Rattus Novergicus) exposed to lead acetate

Characteristics of margarine based on VCO (Virgin Coconut Oil) with the addition of white guava leaf extract (Psidium guajava L.)

Margarine is a water-in-oil emulsion that has stability increases with the addition of an emulsifier. In this research, the margarine was made differently from commercial margarine because of the raw materials using VCO (Virgin Coconut Oil) and white guava leaf extract contains high antioxidant content. This research aimed to determined the physicochemical and sensory characteristics of VCO margarine with the addition of white guava leaf extract used Completely Randomized Design (CRD) with two factorials, the ratio of CBS fat and VCO oil (60:40, 50:50, 40:60 g) and the concentration of white guava leaf extract (20%, 40%, 60%) with tworepetitions. The combination of 60% CBS Fat: 40% VCO oil with the addition of 60% white guava leaf extract is the best formula containing a high antioxidant activity. The result of this combination obtained moisture content of 9.91%, fat content of 87.64%, acid number of 2.18 mgKOH/g, free fatty acids of 0.18%, emulsion stability of 91.62%, and antioxidant activity of 88.70%. In the organoleptic test, the color of VCO margarine was 3.04; the taste of margarine was 3.20 (slightly different from the control), the texture (greasing power) of margarine 2.07 (almost as same as the control), the aroma of margarine 3.73 (slightly different from control), and overall preference of margarine 3.67 (rather like). The results of this research indicated that VCO (Virgin Coconut Oil) margarine with the addition of white guava leaf extract affects the overall chemical and organoleptic tests.

Effect of Psidium guajava Juice on The Seminiferous Tubules Diameter and Epithelium Thickness in Rattus norvegicus Exposed by Lead Acetate

Lead is one of humans and animals' most common and hazardous heavy metals. This study aimed to investigate the effect of white guava (Psidium guajava) fruit juice on the seminiferous tubule diameter and epithelium thickness in rats (Rattus norvegicus) exposed to lead acetate. The research design was a completely randomized design (CRD). A total of 25 male rats with an average weight of 200 grams were used for the study, divided into 5 treatment groups, each consisting of 5 rats. The treatments were as follows: the control group (C) was given distilled water orally; the T0 group was induced with lead acetate (50 mg/Kg BW) orally; the T1, T2, T3 groups were induced with lead acetate (50 mg/Kg BW) and then given 25%, 50%, and 100% concentration of white guava fruit juice, respectively. All the treatments were conducted for 14 days. The histopathology slides of the testis were made with HE staining, and the seminiferous tubule diameter and epithelium thickness were measured. The data were analyzed using One Way ANOVA and Duncan test (p<0.05). The results showed that the control group (C) which was given distilled water only had a seminiferous tubule diameter and epithelium thickness of 336.24±23.32 µm and 66.46±4.39 µm, respectively. The T0 group which was induced with lead acetate only showed a reduction in the diameter and epithelium thickness of seminiferous tubules (243.38±49.35 µm and 44.08±14.45 µm). The members of the T1, T2 and T3 groups showed positive effects on the diameter (323.49±22.82 µm; 314.41±13.04 µm; 325.04±16.88 µm, respectively) and epithelium thickness (56.36±3.36 µm; 60.50±3.81 µm; 66.744±9.50 µm, respectively). There was no significant difference reported between each group. The administration of guava juice to rats induced with lead acetate can positively affect the diameter and epithelium thickness of seminiferous tubules.

Effect of white guava (Psidium guajava L.) fruit juice on the quality of lead acetate induced rats (Rattus norvegicus) spermatozoa

This study aims to determine the effect of the administration of white guava (Psidium guajava L.) fruit juice on spermatozoa plasma membrane integrity (PMI), morphological abnormality, viability, and motility of lead acetate induced rats (Rattus norvegicus). Twenty-five male rats were divided into five groups: NC (negative control) group, rats were administered with distilled water twice daily at four-hour intervals; T0 (positive control) group, rats were administered daily with lead acetate 50 mg/kg bw and distilled water four hours later; T1, T2, and T3 groups, rats were administered daily with lead acetate 50 mg/kg bw and 0.5 mL of 25, 50, and 100% white guava fruit juice four hours later. The treatment of the rats was conducted for 14 days, and on day 15, all rats were sacrificed to assess the spermatozoa quality. Data was analyzed using ANOVA followed by Duncan's multiple range test at a confidence level of 95%. The results showed that exposure to lead acetate (T0) caused lower spermatozoa PMI, viability, and motility as well as higher spermatozoa morphological abnormalities (p <0.05) compared to those of the T0 group. Administration of white guava fruit juice starting at a dose of 25% (T1) resulted in higher spermatozoa motility, viability, and PMI as well as lower spermatozoa morphological abnormalities (p <0.05) compared to rats in the T0 group. It could be concluded that white guava fruit juice maintained the spermatozoa quality of lead acetate induced rats.

Effect of white guava (Psidium guajava L.) fruit juice on the quality of lead acetate induced rats (Rattus norvegicus) spermatozoa

This study aims to determine the effect of the administration of white guava (Psidium guajava L.) fruit juice on spermatozoa plasma membrane integrity (PMI), morphological abnormality, viability, and motility of lead acetate induced rats (Rattus norvegicus). Twenty-five male rats were divided into five groups: NC (negative control) group, rats were administered with distilled water twice daily at four-hour intervals; T0 (positive control) group, rats were administered daily with lead acetate 50 mg/kg bw and distilled water four hours later; T1, T2, and T3 groups, rats were administered daily with lead acetate 50 mg/kg bw and 0.5 mL of 25, 50, and 100% white guava fruit juice four hours later. The treatment of the rats was conducted for 14 days, and on day 15, all rats were sacrificed to assess the spermatozoa quality. Data was analyzed using ANOVA followed by Duncan's multiple range test at a confidence level of 95%. The results showed that exposure to lead acetate (T0) caused lower spermatozoa PMI, viability, and motility as well as higher spermatozoa morphological abnormalities (p <0.05) compared to those of the T0 group. Administration of white guava fruit juice starting at a dose of 25% (T1) resulted in higher spermatozoa motility, viability, and PMI as well as lower spermatozoa morphological abnormalities (p <0.05) compared to rats in the T0 group. It could be concluded that white guava fruit juice maintained the spermatozoa quality of lead acetate induced rats.

Characteristics of Guava Probiotic Drink on Various Fruit Type and Fermentation Time

Guava (Psidium guajava) is a fruit that may be used as raw material for probiotic drinks. Guava contains fructose, and glucose which are used by lactic acid bacteria during the fermentation process. Use guava as the basic ingredient of probiotic drinks can increase the selling value of guava. The production of guava probiotics involves the bacterium Lactobacillus casei FNCC 0090 as a probiotic agent. This study aimed to determine the effect of fermentation time and type of Psidium guajava fruit on the characteristics of probiotic drink from guava. This study used a Randomized Complete Block Design (RCBD) with a factorial pattern with two factors, factor I was the time of fermentation (20, 24, 28 hours) and factor II was the type of fruit (red guava, white guava, crystal guava). The data obtained were analyzed using ANOVA and if there was a significant difference between treatments, it was continued by further testing at 5% DMRT level. Crystal guava juice probiotic drink fermented for 28 hours was the best treatment, with the resulting physicochemical characteristics, namely pH 3.3; total BAL 9.09 log CFU/ml, total acid 0.89%, total sugar 5.38%, vitamin C content 152.24 mg. The resulting organoleptic properties include color, aroma, taste, overall 3.4 (slightly like), 3.65 (slightly like), 4.55 (like), 3.60 (slightly like).

Microbiomes Associated With the Surfaces of Northern Argentinian Fruits Show a Wide Species Diversity.

The fiber, vitamin, and antioxidant contents of fruits contribute to a balanced human diet. In countries such as Argentina, several tropical fruits are witnessing a high yield in the harvest season, with a resulting surplus. Fruit fermentation using autochthonous starter cultures can provide a solution for food waste. However, limited knowledge exists about the microbiota present on the surfaces of fruits and the preceding flowers. In the present exploratory study, the microbiomes associated with the surfaces of tropical fruits from Northern Argentina, such as white guava, passion fruit and papaya were investigated using a shotgun metagenomic sequencing approach. Hereto, one sample composed of 14 white guava fruits, two samples of passion fruits with each two to three fruits representing the almost ripe and ripe stage of maturity, four samples of papaya with each two to three fruits representing the unripe, almost ripe, and ripe stage of maturity were processed, as well as a sample of closed and a sample of open Japanese medlar flowers. A considerable heterogeneity was found in the composition of the fruits’ surface microbiota at the genus and species level. While bacteria dominated the microbiota of the fruits and flowers, a small number of the metagenomic sequence reads corresponded with yeasts and filamentous fungi. A minimal abundance of bacterial species critical in lactic acid and acetic acid fermentations was found. A considerable fraction of the metagenomic sequence reads from the fruits’ surface microbiomes remained unidentified, which suggested that intrinsic species are to be sequenced or discovered.

Viability and Vigor of White Guava (Psidium guajava L.) Seeds in Different Stages of Maturation

The white Guava (Psidium guajava L.) is a native fruit tree belonging to the family Myrtaceae, which has a lot of rusticity, adapting to various edaphoclimatic conditions. White Guava is a fruit native to tropical America and the most cultivated species of the Myrtaceae family. It is an excellent source of vitamin C and has an appreciable amount of minerals such as calcium, phosphorus, and iron. The objective of this work was to determine the viability and vigor of white guava seeds at different stages of fruit maturation. The experiment was carried out in the greenhouse of the Federal Institute of Education (IFTO), Science and Technology of Tocantins, in the city of Gurupi – Tocantins - Brazil, between February 17 and July 28, 2020. The white guava seeds collected directly from the fruit were used, which were harvested in the urban region of Gurupi – Tocantins - Brazil in February 2020. Root and shoot length, number of leaves, first emergency count, and seedling emergence were evaluated. White Guava seeds, taken from ripe fruits, provided the highest viability and vigor values.

Potency of Guava Shoot Extract as a Control Means Against Diaphorina Citri

Abstract Citrus production in Indonesia and the world is facing a serious problem by CVPD attacks. Diaphorina citri is the vector of the disease. Guava leave extract is able to be proposed as prospective control means for the vector. Investigation was conducted to identify the repellent effect of guava leaves to adult of D. citri and the attractiveness to its predator, Menochilus sexmaculatus. Repellent effect of grinded dried of upper, middle, bottom shoot of non-seed, white, and red guava shoots to D. citri and M. sexmaculatus were determined in Y-tube olfactometer. The result showed that repellence effect to D. citri was on guava shoots odor sources. Repellence effect was highest on white guava shoots, followed by non-seed guava and red guava. Repellent effect was 80.7%, 72.7%, and 70.0% respectively. However they did not have any repellent effect to M. sexmaculatus. Guava shoots had the attractiveness effect to M. sexmaculatus adult. The effect was higher on upper, middle, and bottom shoot of red guava, and white guava, and middle shoot of non-seed guava than on upper shoot of citrus. Exception phenomenon was found on upper and bottom shoot of non-seed guava. The attractiveness on those shoots was lower than on citrus leaves. It was able to use guava shoots to repel D. citri and to attract M. sexmaculatus adult as a part of control means of D. citri vector of CVPD disease.

Physicochemical and Processing Qualities of Guava Varieties in Kenya

ABSTRACT Despite Kenya’s favorable climate for both exotic and indigenous commercial guava production, neglect has limited research on the fruits’ physicochemical and processing qualities. The white-fleshed, red/pink-fleshed guava, and, to a lesser extent, strawberry guavas that grow in different agroecological zones are the most common Kenyan varieties. The purpose of this study was to determine the physicochemical properties and processing qualities of the common Kenyan guava fruits. A completely randomized study design was used to profile the fruits' physicochemical composition and processing qualities. Approximately 1000kg of the red and white-fleshed guava fruits and 150 kg of strawberry guavas were procured in duplicates from randomly selected trees in farms within Taita Taveta and Kitui counties. These were pooled into respective varieties and subjected to triplicate batches for the analysis of physicochemical and processing qualities. The fruits had distinct flesh colors and sizes that varied significantly (p<0.05), with shapes ranging from oval to round to pear-shaped. The chemical composition of the fruits varied significantly (p<0.05), with a PCA biplot explaining approximately 58% of the variability due to intra (61%) and inter (39%) varietal differences. The strawberry guava’s vitamin C levels were significantly (p=0.0001) lower than the red and white guavas’, at 164.11±11.85, 1365.15± 50.56 and 1665.56±126.50 mg100−1g, respectively. The white-fleshed guavas, on the other hand, were low in β-carotenes (0.04±0.06 mg100−1g) in comparison to the red-fleshed (1.98±0.62mg100−1g) and strawberry guava (1.55 ± 0.30mg100−1g). The strawberry guavas had significantly (p<0.05) higher mineral and total flavonoids contents whereas the total phenolics (1649.14±329.70mgGAE100−1g) and antioxidant activities (1989.14±383.47µMTE100−1g) were significantly (p=0.048) higher in the red-fleshed guava. While strawberry production would be a processing constraint, the red-fleshed guavas had significantly (p<0.05) higher beta-carotene, phytochemicals, and minerals than the white, and therefore best suited for processing.

Effect of pulping methods on the physicochemical properties of the Kenyan red and white‐fleshed guava pulp

AbstractBackgroundAlthough fruit pulping is a highly effective global practice for ensuring a steady supply of fruit for processing during the off‐season, industrial pulping of Kenyan guava cultivars is lacking, contributing to their annual losses. The present study compared the yield characteristics, physicochemical profile, and nutrient retention of pulp extracted from white and red‐fleshed Kenyan guavas using cold and hot extraction methods.ResultsThe pulp yield was highest in the red guava with the pulp to by‐product ratio being significantly (p &lt; 0.05) higher at 2.58, 2.97, and 3.30 for cold, hot water, and steam‐blanched compared to 1.66, 1.95, and 2.03 for the white guava respectively. Although hot extraction methods resulted in significantly (p &lt; 0.0001) higher yields (67%–77%) compared to the cold (62%–73%), the heat‐labile nutrients were affected with as much as 60% and 64% of the white and the red guava's vitamin C being lost. The steam blanched pulps exhibited significantly (p &lt; 0.0001) high overall color changes (∆E) ranging from 22–30 in the pasteurized white guava pulp compared to the red's (−0.24–6). The cold extraction method resulted in better retention of β‐carotene (1.9 ± 0.4 mg), zinc (5.6 ± 2.1 mg), iron (20.1 ± 8.6 mg), flavonoids (241.3 ± 56mgCE), phenolics (1548.7 ± 25.8mgGAE) and antioxidant activities (1998.6 ± 333μMTE) per 100 g in the red guava pulp.ConclusionCompared to the white cold‐extracted pulp, the red guava pulp was more suitable for further processing due to its high nutrient retention, high pulp to by‐products ratio, and textural properties therefore recommended for the adoption of processing the Kenyan guava cultivars.

Polygalacturonase from Aspergillus japonicus (PGAj): Enzyme production using low-cost carbon source, biochemical properties and application in clarification of fruit juices

Aspergillus japonicus polygalacturonase (PGAj) was produced using passion fruit peel, a residue from the agricultural and juice industries, as a low-cost carbon source. The biochemical properties of the enzyme and its application in the clarification of fruit juices were investigated. The maximum PGAj production was obtained using solid state fermentation (SSF) in 48 h (227.75 ± 13.1 U). PGAj was purified in two chromatography steps with a specific activity of 7.9 U/mg protein, 2.9 -fold purification, and 81% final yield, exhibiting a molecular weight about 40 kDa. The optimal pH and temperature for PGAj activity were pH 4.0 and 55 °C, respectively. Moreover, the PGAj enzyme retained up to 90% of its initial activity for 4 h at pH 4.0, 5.0 and 6.0. The enzyme maintained 83% residual activity after 20 min at 50 °C. PGAj best preferred citrus pectin (8.45 ± 1.6 U/mg protein) as substrate. The best results for juice clarification using 3 U/mL PGAj were obtained with the pulp of Palmer and Tommy mango varieties, white guava, banana, and apple, with increases of 65%, 41%, 40%, 11%, and 9.4% in transmittance values, respectively, compared to the control. This was superior to that obtained using commercial pectinase for some of the pulps, as 49% and 21% for Palmer and Tommy mango pulps, respectively. Thus, PGAj may be suitable for application as a clarifying agent in the fruit juice industry. • Polygalacturonase (PGAj) was produced using a low-cost carbon source (passion fruit peel). • PGAj was obtained in 48 h solid state fermentation (SSF). • Better clarification of mango juice achieved with PGAj than with commercial pectinase.

Gel Formulation from Ethanol Extract of The Leaf of White Guava (Psidium guajava L.)

White guava is a plant that can grow easily in Indonesia. As a source of vitamin C, white guava leaves have been used as antidiarrheal drugs. Some studies state that white guava leaves contain antioxidants. Aside from having a selling value, white guava leaves are also used as raw materials for facial cosmetics, namely as raw materials for gel. Flavonoids are a large family of plant secondary metabolites that have various and amazing biological functions, including as antioxidants. The study aims to determine the gel preparation formulation of the white guava leaf extract (Psidium guajava L.) as a good antioxidant and the characteristics of the preparation. To extract the active substance in simplicia, maceration is used by using ethanol extract processes. The gel making uses a CMC-Na base. Formulation I uses a concentration of CMC-Na 0.1 gram. Formulation II uses a concentration of CMC-Na 0.3 grams. Formulation III uses a concentration CMC-Na 0.6 gram. The main raw material is 0.2 grams of white guava leaf ethanol extract for each formulation. The maceration process uses 70% ethanol. 250 grams of white guava leaves are used. The yield obtained was 13.92%. The gel product was analyzed organoleptic test, pH test, dispersion test, homogeneity test, and adhesion test. The results showed that the CMC-Na 0.1-grams, 0.3 grams CMC-Na, and 0.6-grams CMC-Na had a distinctive odor of white guava leaves, brownish color, and thick concentration. The gelling product is homogeneous and pH of 6. The formulations under CMC-Na 0.6 grams have good dispersibility. All formulations have good adhesion. The adhesion is more than 4 seconds. The conclusions are the formulation with CMC-Na 0.6 grams fulfills the requirements for topical gel preparation.

Evaluation of the Vitamins and Possible Nutrient Composition of Local and Improved Specie of Guava Flesh (Psidium guajava)

Background and Objectives: Guava (Psidium guajava) belongs to the family Myrtaceae. It has been cultivated in Nigeria one of the most common fruits in Nigeria. It has become popular because of its availability almost throughout the year. The objective of this study is to evaluate the nutritional and vitamin contents of the flesh of the local and improved guava species.&#x0D; Materials and Methods: Proximate components were determined using the AOAC method for the moisture, ash, crude lipid, nitrogen content (crude protein) and Carbohydrate. Vitamins A, B1, B2, B3, B6 and B12 were analyzed using standard methods.&#x0D; Results: The result showed that moisture and carbohydrate content of the improved white guava flesh is low compared with the local white guava species (9.8825 and 14.4015%) and (56.378 and 62.802%), respectively. The ash, fat, fibre and protein content of the improved white guava flesh are high compared with the local guava species (11.25 and 5.15%), (5.55 and 1.335%), (6.6145 and 6.5865%) and (10.325 and 8.225%). Improved White guava flesh is relatively low in Vitamin A, vitamin B3, vitamin B6 and vitamin C compared to local white guava flesh, while the local white guava flesh is relatively poor in vitamin B1, vitamin B2 and vitamin E compared to improved white guava flesh.&#x0D; Conclusion: The present findings suggest guava flesh as a considerable source of nutrients in the diet and may have health and economic benefits due to its vitamins, and nutritional composition.

Integrating proteomics and metabolomics approaches to elucidate the ripening process in white Psidium guajava

Psidium guajava (guava) exhibits a high content of biomolecules with nutraceutical properties. However, the biochemistry and molecular foundation of guava ripening is unknown. We performed comparative proteomics and metabolomics studies in different fruit tissues at two ripening stages to understand this process in white guava. Our results, suggest the positive contribution of ethylene and abscisic acid (ABA) signaling to the regulation of biochemical changes during guava ripening. We characterized the modulation of several metabolic pathways, including those of sugar and chlorophyll metabolism, abiotic and biotic stress responses, and biosynthesis of carotenoids and secondary metabolites, among others. In addition to ethylene and ABA, we also found a differential accumulation of other growth regulators such as brassinosteroids, cytokinin, methyl-jasmonate, gibberellins and proteins, and discuss their possible implications in the intricate biochemical network associated with guava ripening process. This integrative approach represents a global overview of the metabolic pathway dynamics during guava ripening.

Assessment of renal and hepato-protective potential of guava leaves in male Sprague dawley rats.

Present research project was an attempt to explore the functional/nutraceutical worth of guava leaves from two locally grown varieties (Ruby & Safeda). For the purpose, guava leaves extract was fed to experimental male Sprague Dawley rats to explore the nutraceutical potential of guava leaves against hepatotoxicity. Two studies were performed on two types of rats i.e. study I (normal rats), study II (hepatotoxic rats). In both studies, 250 mg/kg each of pink guava leaves extracts (T1) and white guava leaves extracts (T2) was added in the feed. Feed intake and body weights of the rats were recorded. At the end of the first and eighth week of study, the blood samples of the rats were analyzed to check the effect of guava leaves extracts on renal functioning (Alkaline Phosphatase, Alanine Transaminase and Aspartate Transaminase) as well as liver functioning parameters including urea and creatinine. In both studies, comparatively higher feed consumption was observed in the control group than the rest of the treatments. At the end of study I, the highest weight (207±9.21 g) was observed in T0 whereas, during study II, the maximum value (202±5.58 g) was found in T2 (rats consuming white guava leaves extract) that indicates its effectiveness against hepatotoxicity. Regarding renal functioning tests, pink guava leaves were more effective in decreasing urea and creatinine levels in rats as compared to the white guava leaves in both study plans. Likewise, in each of study trial, pink guava leaves were more effective in reducing AST, ALT and ALP than white guava leaves and control. From the present investigation, it is deduced that guava leaves were effective against hepatotoxicity.

Neuroprotection of Tropical Fruit Juice Mixture via the Reduction of iNOS Expression and CRH Level in β-Amyloid-Induced Rats Model of Alzheimer's Disease.

This study aimed to determine the effects of tropical fruit juice mixture (pomegranate, white guava, and Roselle) on biochemical, behavioral, and histopathological changes of β-amyloid- (Aβ-) induced rats. Formulation 8 (F8) of tropical fruit juice mixture was chosen for this present study due to its high phenolic content and antioxidant capacity. Forty Wistar male rats were divided into five groups: dPBS (sham-operated control), dAβ (Aβ control), JPBS (F8 and PBS), JAβ (F8 and Aβ), and IBFAβ (ibuprofen and Aβ). F8 (5 ml/kg BW), and ibuprofen (10 ml/kg BW) was given orally daily for four weeks before the intracerebroventricular infusion of Aβ for two weeks. Histological analysis and neuronal count of hippocampus tissue in the Cornu Ammonis (CA1) region showed that supplementation with F8 was able to prevent Aβ-induced tissue damage and neuronal shrinkage. However, no significant difference in locomotor activity and novel object recognition (NOR) percentage was detected among different groups at day 7 and day 14 following Aβ infusion. Only effect of time differences (main effect of day) was observed at day 7 as compared to day 14, where reduction in locomotor activity and NOR percentage was observed in all groups, with F (1, 7) = 6.940, p < 0.05 and F (1, 7) = 7.152, p < 0.05, respectively. Besides, the MDA level of the JAβ group was significantly lower (p < 0.01) than that of the dPBS group. However, no significant changes in SOD activity were detected among different groups. Significant reduction in plasma CRH level (p < 0.05) and iNOS expression (p < 0.01) in the brain was detected in the JAβ group as compared to the dAβ group. Hence, our current findings suggest that the tropical fruit juice mixture (F8) has the potential to protect the rats from Aβ-induced neurotoxicity in brain hippocampus tissue possibly via its antioxidant properties and the suppression of iNOS expression and CRH production.

The effects of drying methods on chemical profiles and antioxidant activities of two cultivars of Psidium guajava fruits

Freeze drying (FD), vacuum drying (VD) and hot-air oven drying (OD) were applied to investigate the effects of drying methods on the chemical compositions and antioxidant activities in the white and red guava fruits. 24 compounds were identified, and 10 of them were reported for the first time in guava fruits. The total polyphenols and antioxidant activity in the red guava powder were higher than those in the white guava powder dried under the same condition. Principle component analysis was performed to understand the difference in chemistry composition and the results indicated that the phytochemical composition in different guava powder were mainly influenced by the cultivar but not the drying methods. Quercetin, phloretin, hesperetin and oleanic acid were found to be the main compounds affecting the antioxidant activities in two cultivars. This study also demonstrated that VD induced the release of polyphenols from the matrix, with the additional advantage of reduced processing time and polyphenol oxidation, compared to the other analyzed methods. Our results suggest that vacuum-dried guava powder may be used as a nutritional and functional ingredient.

Flavonoid compounds and antibacterial mechanisms of different parts of white guava (Psidium guajava L. cv. Pearl)

The flavonoid compositions, extracted from leaves, peel and flesh of white guava (Psidium guajava L. cv. Pearl), were identified and quantified by UPLC-ESI-QTOF-MS, HPLC-ESI-MS/MS and HPLC. The main components of three extracts all were quercetin-glycosides, but the proportion and content of quercetin-hexoside and quercetin-pentoside in each extract were different. Based on the measurements of MIC, MBC value and time killing curve, it emerged that 3 flavonoid extracts of white guava had good antibacterial effects on four pathogenic bacteria. White guava leaves flavonoids (WGLF) concentrations of 5.00 mg/mL and 0.625 mg/mL could change the micro-morphology of Escherichia coli and Staphylococcus aureus. It suggested that the antibacterial mechanism of WGLF on gram-positive and gram-negative bacteria was to destroy the structure and function of the cell membrane. It is indicated that the flavonoid extracts from white guava is a potential natural antimicrobial agent.