The Effects of a Gum Arabic-Based Edible Coating on Guava Fruit Characteristics during Storage

Guava is a nutritious fruit that has perishable behavior during storage. We aimed to determine the influences of some edible coatings (namely, cactus pear stem (10%), moringa (10%), and henna leaf (3%) extracts incorporated with gum Arabic (10%)), on the guava fruits’ properties when stored under ambient and refrigeration temperatures for 7, 14, and 21 days. The results revealed that the coating with gum Arabic (10%) only, or combined with the natural plant extracts, exhibited a significant reduction in weight loss, decay, and rot ratio. Meanwhile, there were notable increases in marketability. Moreover, among all tested treatments, the application of gum Arabic (10%) + moringa extract (10%) was the superior treatment for most studied parameters, and exhibited for the highest values for maintaining firmness, total soluble solids, total sugars, and total antioxidant activity. Overall, it was suggested that coating guava with 10% gum Arabic combined with other plant extracts could maintain the postharvest storage quality of the cold-storage guava.

Identification in silico and expression analysis of a β-1-4-endoglucanase and β-galactosidase genes related to ripening in guava fruit

Background Guava fruit softening is a crucial process during ripening and this process involves a number of enzymes that modifies the cell wall. Two of the enzymes that regulate this process are (a) the β-1, 4-endoglucanase 17 (BEG) which hydrolyze β-1, 4 bonds from cellulose and hemicellulose, and (b) β-galactosidase (BGA) that hydrolyzes pectin chains. Bioinformatics and expression analysis information on these genes is limited in guava fruit. Results A fragment of a β-1, 4-endoglucanase 17 (PgE17), and another of a β-galactosidase (PgGa1) were identified. These sequences have a similarity of more than 85% with those reported in the NCBI database. In the guava genome, one homologous sequence was found for PgE17 in Chr 4 and two homologous to PgGa1: one in Chr 3 and the other one in Chr 6. Putative protein PgE17 contains part of the glyco_hydro_9 domain. Putative protein PgGa1 has a part of the glyco_hydro_35 domain. Phylogenetic analysis of PgE17 and PgGa1 revealed that both are highly conserved inside the Myrtaceae family. In silico expression analysis showed that both PgE17 and PgGa1 work in a coordinated way with other cell wall modifier enzymes. Expression of these genes was found in all the guava samples analyzed. However, the highest expression was found in the fruit in the breaking and ripe states. Conclusions A β-1, 4-endoglucanase 17, and β-galactosidase 1 sequences were identified. PgE17 and PgGa1 are expressed in all the plant tissues, and fruit ripening states. Although, the highest expression was on breaker and ripe states.

Changes in physiological and biochemical parameters during the growth and development of guava fruit (Psidium guajava) grown in Vietnam

This research examined the ripening time of guava fruit to provide a scientific basis for better harvesting and preservation of these fruits. Biochemical research methods were used to analyse changes in physiological and biochemical parameters according to the growth and development of guava fruit. The fruit took 14 weeks after anthesis to reach its maximum size in terms of length and diameter. The chlorophyll content in guava peel peaked after 10 weeks, decreasing until week 15. The content of carotenoids, which was low at fruit formation, rose rapidly until fruit ripening, while the vitamin C and reducing sugar contents increased continuously and peaked at week 14. A gradual increase was seen in the starch and total organic acid contents from the beginning of fruit formation, with peaks at 10 weeks, followed by a moderate downward trend. The pectin content showed the same trend, as it declined gradually after peaking at 12 weeks. The first 4 weeks showed an increase in the tannin content, which decreased afterward. The study results show that guava fruit should be harvested after physiological maturity and before ripening completely (14 weeks) to ensure that the nutritional value of the fruit is maintained during storage. Highlights• Xa Li guava at 14 week after anthesis to reach its maximum size in terms of length and diameter. • The chlorophyll content in guava peel peaked after 10 weeks, decreasing until week 15. The content of carotenoids, which was low at fruit formation, rose rapidly until fruit ripening.• The vitamin C and reducing sugar contents peaked at week 14. A gradual increase was seen in the starch and total organic acid contents and peaks at 10 weeks, followed by a moderate downward trend. • The pectin content showed the same trend, as it declined gradually after peaking at 12 weeks. The first 4 weeks showed an increase in the tannin content, which decreased afterward.

Changes in the potential distribution of the guava fruit fly Anastrepha striata (Diptera, Tephritidae) under current and possible future climate scenarios in Colombia

Climate change has affected the geographical distributions of most species worldwide; in particular, insects of economic importance inhabiting tropical regions have been impacted. Current and future predictions of change in geographic distribution are frequently included in species distribution models (SDMs). The potential spatial distributions of the fruit fly Anastrepha striata Schiner, the main species of agricultural importance in guava crops, under current and possible future scenarios in Colombia were modeled, and the establishment risk was assessed for each guava-producing municipality in the country. SDMs were developed using 221 geographical records in conjunction with nine scenopoetic variables. The model for current climate conditions indicated an extensive suitable area for the establishment of A. striata in the Andean region, smaller areas in the Caribbean and Pacific, and almost no areas in the Orinoquia and Amazonian regions. A brief discussion regarding the area's suitability for the fly is offered. According to the results, altitude is one of the main factors that direct the distribution of A. striata in the tropics. The Colombian guava-producing municipalities were classified according to the degree of vulnerability to fly establishment as follows: 42 were high risk, 16 were intermediate risk, and 17 were low risk. The implementation of future integrated management plans must include optimal spatial data and must consider environmental aspects, such as those suggested by the models presented here. Control decisions should aim to mitigate the positive relationship between global warming and the increase in the dispersal area of the fruit fly.

PHYSICOCHEMICAL AND SENSORY CHARACTERISTIC OF STARFRUIT-RED GUAVA FRUIT LEATHER AS AFFECTED BY THE ADDITION OF ARABIC GUM

Fruit leather is one of the processed fruit products. It’s shaped similar to thin sheets that can be rolled, has an elastic texture, and has a specific flavour. One of the suitable fruit that can be processed to fruit leather is starfruit and guava. The aim of this research was to study the physicochemical and sensory characteristics of the fruit leather made from starfruit (Dewa variety) and guava which were added with Arabic gum with different concentration (0%, 0.5%, 1%, 2%, and 2.5%). Data were analyzed by analysis of variance (ANOVA) at α = 0.05. The result showed that the addition of Arabic gum had a significant effect on tensile strength, water, ash, vitamin C content, and pH value, but it did not has a significant effect on crude fiber, water activity content, total bacteria, and total yeast and mold. While the addition of Arabic gum had a significant effect on color and texture sensory test. The best fruit leather was determined based on the physicochemical and sensory test, and it showed that the addition of 0.5% Arabic gum was the best. Characteristics of the best starfruit and guava fruit leather were tensile strength value 437.38 gf, water content 7.38%, ash content 2.02%, vitamin C content 77.08%, crude fiber content 1.85%, pH value 4.22, water activity value 0.48 , total bacteria < 2.5 CFU/g, total yeast and mold < 1 CFU/g with golden yellow color, slightly strong starfruit aroma, strong starfruit flavor, and elastic fruit leather texture.

Predicting impact of climate change on habitat suitability of guava fruit fly, Bactrocera correcta (Bezzi) using MaxEnt modeling in India

Maximum entropy (MaxEnt) modeling was used to predict impact of climate change on habitat suitability of guava fruit fly, Bactrocera correcta in India. It is a polyphagus pest on a wide variety of fruit crops. Future prediction of potential habitat of B.correcta was done for the year 2050 and 2070 with RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 climate scenarios. The model preformed better than random with an average test AUC value of 0.75 of 100 replicate tests run. Under the present and future climatic conditions, the model predicted high habitat suitable category for B. correcta in the areas of south-western coastal (Kerala, Karnataka, Tamilnadu, Maharashtra and Gujarat) part of India by 2050 and 2070. Presently absolute unsuitable areas of Indian sub-continent are projected to be slightly suitable for B. correcta by 2070 due to increase in temperature coupled with decrease in cold stress. The predictive modeling approach presented here provides an outline for future risk of B.correcta in India under climate change scenarios, which can be used for its better management strategies.

Bacterial Cellulose Production in The Overripe Guava Juice by Acetobacter xylinum as A Solution to Reduce Organic Waste

The exploration for a new cost-effective carbon source with shorter fermentation process for high yield BC production is still needed. In this study, bacterial cellulose (BC) was synthesized by Acetobacter xylinum using overripe guava juice as a carbon source. The results showed that A. xylinum was able to grow on the overripe guava juice with different concentration and produced BC after two days incubation. In the later on, the BC is called as nata de guava. The overripe guava juice which containing reducing sugar content 23 g /L (substrate 100%) at pH 4 produced the thickest BC (1.267 cm). This study showed due to the high reducing sugar and protein contents in the overripe guava, without the addition of carbon and nitrogen from external sources, BC could be formed. Considering the huge disposal overripe guava fruit waste in Java, the present study provides an alternative methodology to synthesize BC. Besides, most importantly, this study provides a new insight to manage organic waste specifically from overripe guava fruit rather than the waste being thrown away and becoming organic waste generation. Keywords: bacterial cellulose, Acetobacter xylinum, overripe guava, organic waste

Investigation and Evaluation of Impact Bruising in Guava Using Image Processing and Response Surface Methodology

Simulated impact damage testing was investigated by fractal image analysis using response surface methodology (RSM) with a central composite design (CCF) on quality of ‘Glom Sali’ guava for drop heights (0.2, 0.4, and 0.6 m), number of drops (1, 3, and 5) and storage temperature conditions (10, 20, and 30 °C). After 48 h, impacted fruit were determined and analyzed for bruise area (BA), bruise volume (BV), browning index (BI), total color difference (∆E), image analysis for bruise area (BAI), and fractal dimension (FD) at the bruising region on peeled guava. Results showed that the correlation coefficient (r = −0.6055) between ∆E and FD value was higher than ∆E and either BA (r = 0.3132) or BV (r = 0.2095). The FD variable was determined as a better indicator than conventional measurement (BA or BV) for pulp browning and impact bruising susceptibility. The FD variable also exhibited highest R2adj value (81.69%) among the other five variables, as the highest precision model with high determination coefficient value (R2adj) (>0.8) for impact bruising prediction. Recommended condition of the FD variable to minimize impact bruising was drop height of 0.53 m for five drops under storage at 30 °C. FD variable assessed by image analysis was shown to be a highly capable measurement to determine impact bruising susceptibility in guava fruit.