Pulp Color Research Articles

Fruit Physiology and Sugar-Acid Profile of 24 Pomelo (Citrus grandis (L.) Osbeck) Cultivars Grown in Subtropical Region of China

In the present study, the fruit physiology and sugar-acid ratio of 24 pomelo cultivars grown in ten different locations of the subtropical region of China were measured. The contents of soluble sugars and organic acids were quantified using high-performance (HPLC-MS) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), respectively. The results revealed that the physiological and basic quality attributes of 24 pomelo cultivars, including fruit weight, fruit width, fruit length, peel thickness, number of segments, pulp weight, pulp color, soluble solids, and Vitamin C, ranged between 264.63–1945.85 g, 8.60–19.56 g, 7.40–20.70 g, 0.46–3.33 mm, 11–18.66, 210.25–1351.66 g, 8.59–15.14 Brix°, and 34.79–84.58 mg/100 g, respectively. Soluble sugars, i.e., fructose, glucose, and sucrose, ranged between 16.25–24.25, 16.17–24.22, and 19.90–55.28 mg/g, respectively. Similarly, Organic acids, i.e., pyruvate, fumaric acids, succinic acid, tartaric acid, quinic acid, citric acid, malic acid, and cis-aconitic acid, in 24 pomelo cultivars ranged between 0.48–1.84, 0.02–0.45, 0–0.05, 0.01–0.1, 0–0.14, 3.01–11.85, 0.18–1.42, and 0.01–0.16 mg/g, respectively. The pomelo cultivars ‘Hongzuanmi’, ‘Minihong’, and ‘Hangwanmi’ exhibited maximum contents of citric acid and pyruvate and showed ultimately excessive organic acids. Overall, the ‘Guanximi’ and its budding cultivars, i.e., ‘Hongroumi’, ‘Huangjinmi’, and ‘Sanhongmi’, had the best quality fruits having maximum sugar-acid ratio. Correlation analysis showed that total soluble sugars had a significantly positive correlation with sucrose contents, while citric acids, malic acid, and pyruvate were positively correlated with total organic acids. The determined sugar-acid profile of pomelo cultivars provides the basis for future elucidation of key mechanisms regulating sugars and acids biosynthesis in pomelo.

An Overview on Physico-chemical Characteristics and Postharvest Treatments of Litchi (Litchi chinensis Sonn.)

Background: Litchi chinensis is an evergreen and arboreal tree with grey-black bark, shiny branches, and deep green lanceolate dense round shape leaves. The litchi peel is very thin and rigid and comes out easily, revealing jelly-like white color pulp with excellent flavor due to sugar and acid content. Litchi is an excellent source of antioxidants, vitamin C, vitamin Bcomplex and flavonoids that help in the prevention of chronic diseases. Aim: The quality of litchi fruit is generally estimated by aroma volatiles, color, physicochemical parameters, and fruit composition (minerals and vitamins). Worldwide, the concern is rising regarding the use of sulfating agents in vegetables and fresh fruits. Therefore, there is a requirement of declaration from U.S. Food and Drug Administration regulations for its acceptable levels as sulfur dioxide (SO2) is officially defined as a pesticide that is nowadays used as a fumigant for litchi. Conclusion: This review summarizes the outcome of diverse post-harvest treatments, types of packaging, storage period and their effects on physicochemical characters, sensory evaluation, quality retention, and changes during storage of litchi fruit, along with exploring suitable alternative technologies to replace SO2 fumigation.

Ethyl Formate as a Methyl Bromide Alternative for Fumigation of Citrus: Efficacy, Fruit Quality, and Workplace Safety.

Ethyl formate (EF) was evaluated as a potential alternative to methyl bromide (MB) for phytosanitary treatment of imported citrus fruit in the Republic of Korea. Planococcus citri (Risso) (Hemiptera: Pseudococcidae), a mealybug with known tolerance against EF and MB, was used as a representative pest to test efficacy of the two fumigants against eggs. In nine commercial-scale refrigerated container (67.5 m3) trials using imported orange, lemon and grapefruit, EF applied at the currently approved dose for citrus (70 g·m-3 at 5°C for 4 h, developed for Aspidiotus excisus Green (Hemiptera: Diaspididae), a species less EF tolerant than P. citri) resulted in 76.9-98.3% mortality of P. citri eggs. The EF treatment did not affect the sugar content or the color of peel and pulp of the treated fruit. When oranges were treated according to the current MB (64 g·m-3 at >5°C for 2 h) or EF treatment guidelines, the concentration of fumigant around the fruit fluctuated between 9.4 and 185.1 ppm for EF and 9.5-203.0 ppm for MB during the 72-h post-fumigation processes (venting [0-2 h], transportation to storage [2-24 h], and storage periods [24-72 h]) with both EF and MB maintained between 10 and 100 ppm during the storage period. Considering the efficacy of EF, its apparent lack of phytotoxicity, and its more manageable threshold limit value for humans (100 ppm EF compared to 1 ppm MB for an 8-h time weighted average exposure), our results suggest that EF may be a promising alternative to MB for the phytosanitary treatment of imported citrus in Korea.

Genetic Analysis of Yield and Quality Characteristics in Provitamin A Hybrid Cassava Families in Ghana

Cassava is the most widely cultivated and consumed crop in Ghana. Malnutrition is endemic in cassava-producing regions of Africa, partly due to the low micronutrient content of this crop. The aim of this study was to generate genetic information on characteristics such as total carotenoid content, dry matter content, root weight and number, and cassava mosaic disease (CMD), and their possible combination in cassava clones, using a North Carolina II breeding scheme. Five genetically diverse yellow-fleshed clones at advanced selection stages, with CMD resistance, were used as females and two high dry matter content white-fleshed clones, selected from farmers’ fields in Ghana, were used as males. Ten F1 families were generated, and evaluated at two locations in Ghana. General combining ability (GCA) mean squares were larger than specific combining ability (SCA) mean squares for harvest index, CMD, and carotenoid content, indicating additive genetic effects. The positive significant correlations that were observed between pulp color and carotenoid content; carotenoid content and CMD; pulp color and CMD; and pulp color and cortex color, make the screening of large numbers of progenies possible in the cassava breeding program. This could allow breeders to combine carotenoid content and CMD at the early breeding stages through visual assessment of pulp color and CMD symptoms. Large numbers of genotypes can be evaluated and a few can be selected to be quantified for carotenoid content at later stages of the breeding program, to save costs. One of the parents (P6), showed positive GCA effects for carotenoid content, dry matter content, CMD and storage root weight, hence could be used as a parent to generate clones that combine carotenoid content and dry matter content.

GENETIC DIVERSITY AMONG MANGO HYBRIDS IN THE BRAZILIAN SEMIARID REGION1

ABSTRACT The aim of this study was to evaluate mango hybrids obtained by open pollination based on the physical and chemical traits of the fruit, and to analyze the genetic diversity among these hybrids to find plants that produce quality fruit both for direct consumption and for industrial processing. The hybrids under study were generated from seeds produced from crosses with unknown genotypes as a result of open pollination. The unknown genotypes were randomly scattered in areas dedicated to growing a Tommy Atkins variety, and plants were obtained from mango seeds generated through sexual propagation. To assess genetic diversity, cluster analysis was carried out, as well as principal component analysis. Two hybrids were most prominent in terms of fruit weight, fruit length, fruit diameter, pulp weight, and pulp yield, with mean values greater than 245 g for pulp weight and 70% for pulp yield. Regarding fiber content in the pulp, six hybrids had a score of "2", that is, moderately fibrous fruit. For acidity and soluble solids content, the hybrids exhibited variations from 0.19 to 1.06% of citric acid and from 13.1 to 20.6 ºBrix, respectively. For peel color, tones ranging from reddish orange to yellow and green were observed. As for pulp color, there was variation from orange to light yellow tones. There was variability among the mango hybrids regarding the fruit traits analyzed, and hybrids that produce fruit that combine traits of economic interest were identified.

Maduración postcosecha de Pouteria lucuma: Efecto de las condiciones de almacenamiento en los componentes fisicoquímicos, metabolitos y capacidad antioxidante e hipoglucemiante

Inadequate storage conditions can affect the sensory, physicochemical, and functional properties of tropical fruits such as Pouteria lucuma; which is a climacteric fruit, with a pleasant aroma and flavor; Peru being the main producer and exporter of this fruit, postharvest storage conditions have not been studied to maintain its properties. The objective of the research was to evaluate the effect of the storage conditions on the main physicochemical components, primary and secondary metabolites, antioxidant, and hypoglycemic capacity during postharvest ripening, under two storage conditions: ambient (29 °C and 70% RH) and climatic chamber (15 °C and 90% RH). Regarding the physicochemical characteristics, the state of maturity influenced acidity, pH, reducing sugars, starch, dietary fiber, firmness, pulp color and epicarp. In climate-controlled storage, glucose is the only metabolite that increases; while fructose, alcohol sugars and amino acids (Ala and Val), present higher values ​​under ambient conditions; sucrose, organic acids, amino acids (Tyr, Glu, Asp and Thr), β-carotene, total phenolic compounds and total carotenoids were not affected by the type of storage. The measure of antioxidant and hypoglycemic capacity decreased significantly (p < 0,05), showing to be affected only by the state of maturity. The study of the carotenoid profile according to its spectrum (UV-vis) showed the presence of the group of xanthophylls. The results indicate that the state of maturity concerning the storage condition influenced most of the changes studied.

Postharvest ripening of Hass and Méndez avocado fruit cultivars treated with ethephon

A problem in post-harvest of avocado (Persea americana Mill.) is the heterogeneity in fruit ripening, due to differences in the time of fruit set and the inability to ripen on the tree, a situation that causes inconsistencies in quality and differences in the response to preservation and processing technologies. In postharvest, the application of ethylene gas in hermetic chambers has been used to advance ripening; however, the use of ethylene releasers in liquid form (ethephon) has been proposed as an alternative, mainly for the treatment of low volumes of fruit. The present work was carried out in the production zone of Salvador Escalante (Michoacán, Mexico) with the objective of evaluating the effect of the application of two concentrations of ethephon on the time and homogenization of fruit ripening of avocado cultivars (cv.) Hass and Méndez. Fruits with 23.4% (cv. Hass) and 24% (cv. Méndez) of dry matter were harvested; one group was immersed in a solution of ethephon 500 mg/L and the other in 1,000 mg/L, both for 5 minutes; the treated fruits plus a control were stored at 20 °C for 11 days. Changes in respiration, ethylene production, weight loss, firmness, epicarp and pulp color, total phenol, chlorophyll and total carotenoid concentrations were evaluated. The results showed that ethephon doses of 1,000 mg/L in cv. Hass and 500 mg/L in cv. Méndez presented a ripening process 2 days earlier than the control.

Extent of variability in fruit morphological characters of local mango germplasm

A study was conducted on twenty five genotypes of seedling Mangoes to examine fruit morphological characters. Fruit shape of the evaluated germplasm varied enormously and fruits of obovoid, elliptic, round and oblong shapes were found. Fruit apex shape in the evaluated plants was round, acute and obtuse. Depth of fruit stalk cavity was either absent, shallow and of medium type, whereas, fruit neck prominence was absent to slightly prominent in the tested plants. Shape of fruit ventral shoulder was varied and found to be slopping abruptly, rising and then rounded and long curve type in the evaluated germplasm. Fruit beak varies from pointed to perceptible type and fruit sinus was absent to shallow type in the fruits from different plants. Fruit attractiveness varies from very good to excellent and fruit colour from greenish yellow to green colour of fruit skin at maturity was noted in fruits from selected trees. Peel colour of AA-15 was different amongst all the genotypes which were green with red blush. Pulp colour varied from light orange, yellow orange, orange yellow, yellow and light yellow, whereas, pulp texture was soft to intermediate in the evaluated germplasm. Key words: Mangifera indica; Genotype susceptibility; Punjab; India.

Pre-Harvest Oxalic Acid Application Improves Fruit Size at Harvest, Physico-Chemical and Sensory Attributes of ‘Red Flesh’ Apricot During Fruit Ripening

Apricot is a highly nutritive stone fruit which ripens quickly after harvest and exhibits rapid fruit quality deterioration at ambient conditions. The current research work was executed to evaluate the effect of pre-harvest application of oxalic acid (OA); (0, 0.5, 1, and 2mM) on fruit quality of ‘Red Flesh’ apricot during fruit ripening at shelf under ambient conditions (25±1 °C; 60-65% RH). Fruit size, average fruit weight, fruit juice percentage was determined at harvest. While, fruit weight loss, fruit colour, fruit firmness, titratable acidity (TA), soluble solid contents (SSC), ratio of SSC to TA, ascorbic acid, total phenolics content (TPC), anti-oxidative scavenging activity (ASA), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) enzymes activity were determined during fruit ripening. Fruit sensory attributes (fruit pulp colour, fruit taste, fruit flavour and overall acceptability were determined at fruit ripening. Pre-harvest application of 2mM-OA was found the most effective in improving fruit size, average fruit weight, juice percentage at harvest, about 5%, 6% and 15% higher than control, respectively. Additionally, pre-harvest application of 2mM-OA retained higher fruit firmness, ascorbic acid, TPC, ASA and activities of POD, CAT enzymes in apricot fruit during fruit ripening at ambient conditions. On day-5 of fruit ripening 2mM-OA-treated apricot fruit exhibited about 28%, 20%, 17%, 7%, 9% and 23% higher fruit firmness, ascorbic acid, TPC, ASA and activities of POD, CAT enzymes, respectively as compared to control. Moreover, significant lower fruit weight loss (35%), SSC (20%) and SSC:TA ratio (30%) were exhibited by the apricot fruit treated with 2mM-OA than unsprayed apricot fruit. However, fruit treated with 1 mM-OA exhibited better fruit sensory attributes compared to other treatments at fruit ripening. Conclusively, pre-harvest application of 2 mM-OA improved the fruit size, delayed fruit ripening, and retained higher fruit antioxidants of apricot at ambient conditions.

Fruit quality and harvest point determination in white-fleshed dragon fruit

The objective of this study was to evaluate the quality of white-fleshed dragon fruit (Hylocereus undatus) at harvest and postharvest to determine fruit quality and the feasibility of harvesting the fruits at different outer fruit color stages. The treatments consisted of four peel color stages – S1 (<25% red peel), S2 (25%-49% red peel), S3 (50% to 75% red peel) and S4 (>75% red peel) – and two evaluation times (at harvest and one day after full red peel color), which corresponded to 1, 3, 5 and 7 days after harvest for the S4, S3, S2 and S1 color stages, respectively. The total, peel and pulp weights, pulp yield, peel thickness, pulp firmness, pH, total soluble solids and peel, scale and pulp colors were evaluated. The peel and scale colors are reliable indicators of fruit quality. It is possible to extend the postharvest shelf life of the fruits by harvesting at the S1 stage, but this negatively affects yield and final quality; the fruits are smaller and less sweet, making harvesting unfeasible at this timepoint. Despite the higher yield and quality of fruits harvested at a more advanced ripeness stage (S4), the postharvest shelf life is considerably reduced. Thus, fruits at stages S2 or S3 should be harvested to obtain higher yield and quality.

PHYSICAL, CHEMICAL AND SENSORY ATTRIBUTES OF FRUITS OF TEN MANGO VARIETIES GROWN UNDER ORGANIC PRODUCTION SYSTEM

ABSTRACT This study aimed to assess the physical, chemical, and sensory attributes of mango varieties grown under the organic farming. Fruits from ten varieties of mango grown under the organic system in the Chapada Diamantina region, BA, Brazil, were assessed. The following physical and chemical characteristics were assessed: fruit mass, pulp yield, pulp color (L*, C*, and h*), soluble solids (SS), titratable acidity (TA), total carotenoids, and ascorbic acid. The sensory acceptance test was performed with 50 consumers using the nine-point structured hedonic scale and the attributes acidity, sweetness, and firmness of the pulp were assessed using the just-about-right scale. Differences among the varieties of mango grown under the organic production system were observed for physical, chemical and sensory attributes. The varieties showed a percentage of pulp equal or above 60%, which makes them more suitable for processing. According to the PCA analysis, the characteristics soluble solids, total carotenoids, fruit mass, titratable acidity, h* and L* were considered the most important to differentiate the mango varieties evaluated. Ubá and Beta varieties had the highest levels of SS, while Favo de Mel was characterized by the highest values of TA and L*. The varieties Favo de Mel, Palmer, Surpresa, Juazeiro 2, Imperial and Joa had fruits with higher mass and h* values and the varieties Amrapali and Roxa Embrapa 141 had the highest levels of total carotenoids. Imperial, Palmer, Beta and Joa varieties were the most accepted for all sensory attributes.

Study of collection samples of table watermel with unconventional pulp color

Relevance. The study of the collection is one of the main sources of replenishing the source material for the breeding process. The presence of the necessary genetic traits can speed up the breeding process. Therefore, at the Bykovskaya melon breeding experimental station, the genetic diversity of melon plants is assessed and promising samples are selected for use in breeding.Materials and methods. The object of research was samples of table watermelon with an unconventional color of the pulp. The aim of the work is to study and isolate the source material of watermelon for use in the breeding process to create new varieties and hybrids of melon crops. In the course of the study, 12 varieties of table watermelon were identified from 33 varieties of the collection nursery, which are sources of economically valuable traits. The selection was carried out according to the yield, the rate of entry into fruiting, taste, color of the pulp.Results. In the course of the research, the obtained samples of table watermelon with an unconventional color of the pulp were evaluated according to a set of economic characteristics in comparison with the standards: Zenith and Sinchevsky. The analysis of the tested samples made it possible to identify 12 samples by economically valuable traits: 3 samples by early maturity and taste: White sugar lump, White wonder, Golden revenge F1; 7 samples with a high dry matter content, in terms of yield and large fruit: Moon and stars yellowflesh, Sweet Siberian, Orangeglo, Daisy, Clay county yellow meat, Mountain sweet yellow, Tendergold; 2 samples for color and pulp consistency: Early moon beane Bakerlneek, Tenderweet orange. The selected samples meet the modern requirements of the industrial melon growing industry, resistant to stress factors of the environment, good taste and consumer properties.Findings. The obtained experimental data will be used to create a genetic collection of watermelon according to the traits that determine the economic value of the gene pool for further use in the breeding process.

CHARACTERIZATION OF QUALITY ATTRIBUTES OF MANGO CV. 'ATAULFO' AT DIFFERENT MATURITY STAGES

The objective of this study was to evaluate the specific characteristics of three maturation of the 'Ataulfo' mango, as well as the correlation of a non-destructive method as the DA Meter Absorption Difference Index (Turoni), with destructive physical-chemical parameters. The mangoes were harvested at stages 2, 3 and 4, the following variables were determined: loss of mass, length, diameter, shell and pulp color and their coordinates L * a * b *, firmness, DA Index, yield, pH, soluble solids, titratable acidity and vitamin C. The experimental design was completely randomized with ten repetitions. The results were submitted to the test of means and simple correlation. Physical and physico-chemical analyzes such as mass, length, pulp yield, can be used as a basis for determining maturation stages, but the DA Index differentiation of fruits in different maturation classes, in addition to having a good correlation with firmness, SST, ATT and pH, with high coefficients, -0.92, 0.94, 0.97 and -0.93, respectively. Thus, the determination of this index represents a potential tool based on non-destructive analysis to determine the maturation of 'Ataulfo' varieties.

Fig freezing in sugar solutions

The effect of fig freezing in sugar solution on fig’s quality and sensory traits as well as phenolic content during storage was examined. Fresh figs were frozen without any treatment (control - CON), in sucrose solution (30%) (SUC) and sucrose solution (30%) with ascorbic acid (2%) (SUCAA), and stored at -18 ⁰C for 210 days. Samples were analyzed every seventy days for pH, total soluble solids (TSS), sugars and phenolics composition, skin and pulp color, and they were sensorially evaluated. According to ANOVA, storage time showed significant impact on more analyzed parameters than freezing conditions. CON and SUC had the highest TSS, what was also sensorially detected. SUCAA was evaluated with the lowest scores for sweetness and typical fig flavor followed by the highest score for off-taste, off-flavor and off-odor. Contrary to TSS, individual sugars and phenolics were the lowest in CON. SUCAA showed the most brightener skin and the reddest pulp measured by colorimeter, and sensorially it obtained the highest scores for skin and pulp color. Storage time caused TSS and pH decrease, what reflected sensorially as a decrease of fig taste and flavor, as well as the appearance of off-taste, off-flavor and off-odor was also observed. Contrary, individual sugars and phenolics showed increase during storage, and the lowest amounts were present in CON. In conclusion, after 140 days all figs noticeably lost their desirable attributes, where CON fig was sensorially the best evaluated and SUCAA gained the lowest scores.

Mineral Content of Pitaya (Hylocereus polyrhizus and Hylocereus undatus) Seeds Grown in Turkey

Pitaya is one of the most produced tropical fruits in Turkey because of its high economic value. Seeds of this fruit consumed with fruit are an important source due to nutritional and health benefits. In this study mineral and ash content of pitaya seeds were investigated. The research was carried out with two different species of pitaya, Hylocereus undatus (H. undatus) and Hylocereus polyrhizus (H. polyrhizus), which have red shell. H. undatus has a white pulp color while H. Polyrhizus has a red. The ash content of H. polyrhizus and H. undatus pitaya seeds was 2.78% and 4.09%, respectively. The main minerals detected in H. polyrhizus and H. undatus pitaya species were potassium (36.47 mg/kg and 31.99 mg/kg), magnesium (9.15 mg/kg and 9.16 mg/kg), phosphorus (8.99 mg/kg and 8.08 mg/kg), sulphur (6.11 mg/kg and 5.48 mg/kg) and calcium (2.17 mg/kg and 1.90 mg/kg). Mineral content of seeds of H. polyrhizus and H. undatus species were found similar to the pitaya species grown in different tropical countries.

Effect of cold storage on the postharvest quality of different Tarocco sweet orange clonal selections

Fruits of sixteen Tarocco sweet orange (Citrus sinensis [L.] Osbeck) clonal selections were compared for their long-period cold storage aptitude, for fresh fruit consumption. Selections were evaluated, for two consecutive seasons, at harvest (T0) and after 30 (T30), 60 (T60) days of storage at 5 ± 1 °C and 85–90% relative humidity (RH), followed by 7 days of shelf-life at 20±2 °C (T60+7). The following parameters were evaluated: fruit weight, peel and pulp color, initial and residual deformation, elasticity, firmness, juice yield, TSS, pH, TA, total anthocyanin content, and for each control: weight loss and physiological disorders (chilling injury and aging). The selections showed significant variability regarding the physiological disorders, especially at T60+7 with a range of 0.0–0.6 for chilling injury index and a range of values of 0–63% for aging. At T60+7 the weight loss range was between 10.0–14.3%. Regarding overall qualitative parameters, relevant changes were observed for firmness which decreased during the storage, with values ranging from 2.58-5.28 (T0) to 2.56–4.41 (T60+7), and for the anthocyanins which increased from a range of 1.67–39.71 (T0) to 30.47–114.86 mg/L (T60+7), with different values depending on the clonal selections. Based on our results, the clonal selections that showed a better aptitude to long-period cold storage were Gangi, 2B-12–9, Pedalino and Amantea, together with the reference cultivars Meli and Messina. These clones resulted particularly tolerant to chilling injury and aging, they maintained the firmness and the most relevant qualitative traits (TSS and TA) and showed the best fruit external appearance after one week of shelf-life (T60+7).

Removal of colour and lignin from paper mill wastewater using activated carbon from plastic mix waste

The study aimed at the use of char produced during pyrolysis of mix plastic waste. It further focused on producing activated carbon from char and also found its efficacy as efficient adsorbent for treatment of pulp and paper mill wastewater. The activated carbon was characterized in comparison with raw char for their physical, surface and adsorptive properties. Batch type adsorption experiments were carried out using 100 ml wastewater to observe the individual effectiveness using five different variables such as adsorbent dose (0.25–2.0 g), pH (6–10), time (5–24 h), agitation speed (100–200 rpm) and temperature (30–50 °C) by keeping other variables constant which helped to find out the effective range of all the variables. The competency was evaluated on the basis of colour and lignin content of pulp and paper industry wastewater. Once the effective range of different variables was identified, the statistical analysis was conducted to monitor the mutual impact on the reduction in colour and lignin contents in wastewater. From the statistical design applied, the best result was obtained at activated carbon dose (1.25 g), pH (8.0), contact time (7 h), agitation speed (184 rpm) and temperature (40 °C). The study resulted in reduction of 96.48% in colour and 94.25% in lignin at optimized condition in comparison with 87.37 and 80.44%, respectively, at unoptimized conditions. A potential increase in reduction of 9.0% in colour and 14.0% in lignin content was achieved after optimization through statistical design that confirmed its usefulness.

Effect of potassium fertilizers associated with cold storage on peach (Prunus persica L.) quality

Potassium (K) fertilization may affect peach quality and preservation. This study aimed at evaluating the effect of doses of K on physico-chemical and functional characteristics of ‘Sensação’ peaches in the postharvest period. Mass loss, pulp color, total soluble solids, titratable acidity, pH, pulp and skin firmness, total concentrations of phenolic compounds and carotenoids and antioxidant activity were evaluated in fruits. The experiment was a randomized block design in a 5x3 factorial scheme, five doses of fertilizers (0, 40, 80, 120 and 160 Kg ha-1 K2O) and three storage periods (harvest day, 10 days and 20 days in cold storage at 1±1ºC, followed by a day of simulated commercialization at 20±1ºC). Mass loss, pulp firmness, phenolic compounds, antioxidant activity and carotenoids decreased when fruit underwent cold storage, independent of the dosage of K fertilization. Doses of 40 and 160 kg ha-1 K2O applied to the soil lead to a larger number of phenolic compounds and higher antioxidant activity in fruits at harvest time. After cold storage, fertilization with 160 kg ha-1 K2O exhibited the highest antioxidant activity and the lowest mass loss in fruits. Increase in doses of K strengthened the color of peach pulp

Physicochemical characterization and polyphenol oxidase inactivation of Ataulfo mango pulp pasteurized by conventional and ohmic heating processes

Ohmic heating (OH) is an emerging technology with potential for pasteurization and enzyme inactivation in mango pulp. This research aimed to investigate the effect of OH and conventional boiling treatment (CT) at moderate pasteurization conditions (72 °C, 2 min) on the physicochemical characteristics and the polyphenol oxidase (PPO) residual activity in Ataulfo mango pulp. Pulp's physical features, such as titratable acidity (TA) and pH did not show differences (p > 0.05) between treatments, whereas OH increased the apparent viscosity of mango pulp (10.26–15.64%). This effect was associated to a higher release of insoluble fiber. Both thermal treatments affected the color (ΔE values > 5) of mango pulp. PPO inactivation reached 95.7 ± 5.9% after 15 s with both thermal treatments. In silico molecular dynamics suggested that temperature and pH contributed to the PPO inactivation by inducing modifications in its catalytic site and altering the protein-substrate interaction. Our results indicate that OH is an effective technology to inactivate PPO at moderate pasteurization conditions (72 °C, 15 s), with minimal modifications on the physicochemical properties of Ataulfo mango pulp.

Distinguishing three Dragon fruit (Hylocereus spp.) species grown in Andaman and Nicobar Islands of India using morphological, biochemical and molecular traits

Dragon fruit (Hylocereus spp.), an important tropical fruit belonging to the family Cactaceae, is rich in essential nutrients such as vitamins, minerals, complex carbohydrates, dietary fibres and antioxidants. This study aims to distinguish three dragon fruit species well adapted to Andaman and Nicobar Island through morphological (34 quantitative and 26 qualitative traits), biochemical (5 traits) and molecular (14 ISSR primers) characterization. Morphological characterization revealed that presence of considerable amount of genetic variations among them especially for fruit characters viz., colour of peel and pulp. Cladode characters such as number of spines (3–5), length of areoles (mm) as 1–4, margin ribs of cladode (convex or concave) and its waxiness (weak or strong white waxy or light waxy) could be used for identification of three Hylocereus spp. under present study. Highest co-efficient of variation (%) obtained for pulp weight (88.7), whereas, lowest in distance of anthers belowstigma (3.3). Fruit and pulp weight (g) ranged from 26.5–419.3 and 10.3–258.8 with mean value of 204.8 and 125.3, respectively. Comparatively, high phenol (71.3–161.3) and flavonoid (26.6–508.2) content observed in peels than pulp (32.5–130.0 and 45.0–258.2) of fruit indicating higher antioxidant potential. Highest total carotenoids (µg 100 g−1), β-carotene (µg 100 g−1) and xanthophyll (µg g−1) content obtained in pulp on DGF3 (33.8), DGF4 (55.9) and DGF3 (32.7), whereas, in peel on DGF2 (24.3), DGF4 (18.5) and DGF2 (24.1), respectively. DPPH-based scavenging activity (%) revealed higher scavenging activity of peels (55.6–81.2) than pulp (36.0–75.3) extracts. Comparatively, ABTS-based scavenging activity (%) was found more than DPPH-based one. Sixteen ISSR primers screened, 14 were produced 178 reproducible amplified bands. Number of amplified bands varied from 5 in UBC887 to 19 in UBC811 with an average of 12.71 bands per primer. Range of polymorphic bands and % polymorphism observed were 1–13 and 20.0–92.8, respectively. The polymorphic information content value of ISSR marker ranged from 0.42 (UBC895) to 0.91 (UBC 856). Cluster analysis distinguished three different Hylocereus species on the basis of geographic origin and pulp colour by forming separate groups and two genotypes each showed 52% (DGF1 and DGF3) and 76% (DGF2 and DGF4) genetic similarity. Key traits identified for distinguishing three different Hylocereus species were: Pulp/ peel colour of fruits, number of spines and length of areoles in cladode. Genotypes with high carotenoid and xanthophylls content (DGF4 and DGF2) identified under present study may be of industrial importance for development of nutraceutical products to meet out the vitamin-A deficiency among humans in tropical regions needed future focus.