Total Titratable Acidity Content Research Articles

Natural antioxidants and postharvest quality of grape tomatoes at different ripening stages

The objective of this work was to characterize the 5 classes of grape-type cherry tomatoes of sweet heaven variety based on the instrumental color. The experiment was carried out in a completely randomized design (CRD), with five stages of maturation (treatments) and five replications. The contents of the bioactive compounds (total phenolic compounds, total carotenoids, lycopene and flavonoids) and the physicochemical characteristics (pH, total soluble solids, total titratable acidity and SST/ATT ratio) were evaluated. Data were submitted to the Shapiro-Wilk normality test and the Bartlett homogeneity test, and for those that did not meet, the Kruskall Wallis nonparametric equivalent ANOVA test was used, followed by Dunn's test. The results showed a reduction in the total titratable acidity content; an increase in pH, total soluble solids and SST/ATT ratio. The samples collected in the mature stage showed the highest concentrations of bioactive compounds and antioxidant capacity. Despite presenting superior characteristics in relation to the other stages, the harvest of tomatoes at this stage becomes compromised due to their perishability to handling. Yet, the joint assessment of quality attributes can improve the identification of maturation stages, in order to ensure the delivery of a product that satisfies consumer requirements.

Nondestructive detection of tomato quality based on multiregion combination model

AbstractTo quickly and accurately identify the quality of tomatoes, a method was proposed to predict the total soluble solid content (SSC), total titratable acidity (TA), and vitamin C (VC) content of tomatoes based on a multiregion combined model of the visible–near‐infrared spectrum. The results show that the competitive adaptive re‐weighted sampling algorithm combined with the partial least squares regression (CARS‐PLSR) model has the best prediction effect on SSC, TA, and VC content in “stem + equator”, “stem + bottom” and “stem + bottom” combinations. The prediction accuracy is 97.2%, 96.7%, and 97.7%, respectively, and the relative percent deviation (RPD) value is 5.870, 5.401, and 5.942, respectively.Practical ApplicationThis indicates that the CARS‐PLSR model based on the multiregion combination of visible–near‐infrared spectroscopy is reliable for predicting tomatoes' SSC, TA, and VC content. The results provide a theoretical basis for developing a portable fruit quality detector.

Changes in physicochemical properties at different development stages of Hexachlamys edulis fruit, an underutilized South American species

The aim of this work was to study the evolution of fruit size and weight together with the soluble solid and total titratable acidity contents during development of Hexachlamys edulis fruit. Also, the patterns of accumulation of chlorophylls, carotenoids, phenols and antioxidant activity were analysed to define the optimal time for harvesting to obtain maximum nutraceutical characteristics. Fruits were harvested from H. edulis plants growing at the experimental field of the University of Morón (Moreno, Buenos Aires, 34°35′4.98″ SL, 58°48′52.09″ WL, 14 m.a.s.l.). Fresh fruit weight was significantly higher in Medium ripe, Ripe and Overripe fruits (40.1, 39.6 and 38.5 g, respectively) than in Unripe fruits (19.5 g). Soluble solids/total titratable acidity was significantly higher in Overripe fruits (7.3) than in Unripe, Medium ripe and Ripe fruits (3.7–4.5). Total polyphenols were maximum in Unripe fruits (905.8 mg tannic acid/100 g fresh fruit weight) decreasing during the fruit development (426.2–130.4 mg tannic acid/100 g fresh fruit weight). Also, DPPH radical scavenging activity was significantly higher in Unripe fruits (75.7%) compared with Medium ripe, Ripe and Overripe fruits (64.1–17.0%). Positive and significant correlations were observed between total polyphenol content and DPPH radical scavenging activity at each extract concentration (r = 0.74, 0.87, 0.74 and 0.60 for 1.25; 2.50; 5.00 and 12.50 mg/mL, respectively). Total carotenoid content increased during fruit development while at the same time decreased chlorophyll content. Chlorophyll b is the main chlorophyll found. Chromatographic analysis showed that lutein is the main carotenoid found in H. edulis fruits, followed by β-cryptoxanthin and β-carotene. As shown by the chromatograms at 280 nm, the concentration of biophenols and the complexity of the biophenol profile decreases during fruit development. Levels of polyphenols and pigments together with the antioxidant activity allow us to consider H. edulis fruit as a functional food.

Quality of guava fruits bagged with different materials in an organic system

This study aimed to evaluate the interference of bagging materials on the incidence of insect larvae and the physical and chemical quality of the guava cv. Paluma in an organic system. The experimental design was in randomized blocks with seven treatments and four replications of 25 fruits each. The bagging materials (treatments) were: nonwoven fabric (TNT), transparent plastic bag, white plastic bag, parchment paper, kraft paper, and non-bagged fruits (control). The titratable acidity (TA), ascorbic acid, soluble solids (SS), SS/TA ratio, fresh mass, fruit diameter, fruit length, appearance, and fruit fly incidence were evaluated. Fruit bagging increased the fresh fruit mass, except the tulle bag, which did not change fruit diameter but increased fruit length. There was a high incidence of fruit flies in the non-bagged fruits (100%) and in those with tulle bags (56.53%), reduced to 2.15% when using parchment paper, and reaching the absence of bored fruits when using nonwoven fabric, transparent plastic, and white plastic bags, materials that provided the highest percentages of marketable fruits. All bagging materials did not change the total titratable acidity content and the SS/TA ratio; however, all of them reduced the content of total soluble solids, except the tulle bag. Fruit bagging with nonwoven fabric and parchment paper increased the content of ascorbic acid. Fruit bagging with parchment paper, plastic bag, and nonwoven fabric are efficient in the organic production of guavas for preventing the infection by insect larvae and maintaining the physical and chemical quality of the fruit.

Fruiting and quality attributes of cambui (Myrciaria floribunda (West ex Willd.) O. Berg in the Atlantic Forest of northeast Brazil

Cambuizeiro is a fruit native to the Atlantic Forest biome that has potential for ornamental use and for human consumption, either raw or processed, due to the organoleptic characteristics of its fruits. Accordingly, the study objective was to evaluate the fruiting periods and quality attributes of two types of cambuizeiros, differentiated by fruit color. The plants studied were from a natural population from the Embrapa Tabuleiros Costeiros Experimental Station, in the municipality of Itaporanga d’Ajuda, state of Sergipe, Brazil. A total of 20 plants, 14 with orange and six with purple fruit, seven days after anthesis (DAA), were evaluated weekly during fruiting. After harvest, the fruits were evaluated for weight, length, width, number of seeds, pH, soluble solids (SS), total titratable acidity (TTA) and vitamin C content. There was heterogeneity in the ripening of the two cambuizeiro types. The highest peak of ripening occurred at 63 DAA (83.2% of orange and 68.3% of purple fruits). The purple fruits had superior physical attributes. However, the pulp of the orange colored fruits had a higher TTA content. Both types of fruits have potential characteristics for commercial exploration and use.

Effect of different rootstocks on Persian lime (Citrus latifolia T.) postharvest quality

Mexico is the world’s leading Persian lime (Citrus latifolia T.) fruit producer and exporter. The use of rootstocks in citrus may increase fruit quality; however, the most used rootstock in Mexico is Sour orange, which is susceptible to the citrus tristeza virus. The objetive of this work was to evaluate the effect of rootstock (Sour orange, Volkamerian lemon, Flying dragon, Swingle citrumelo and C-35 citrange) on Persian lime fruit quality parameters. Peel thickness, juice content, pH, total titratable acidity (TA), total soluble solids (TSS), weight loss, pectin content, organic acids, sugars and characterization of essential oil components were evaluated. The use of rootstocks had no effect on juice content, pH, TA, organic acids (oxalic, malic and ascorbic) and sugars content (fructose, glucose and sucrose). Fruits from trees grafted on Sour orange and Volkamerian lemon showed the highest pectin yield, while Volkamerian lemon and Flying dragon showed the highest content of citric acid. The aromatic profile of Persian lime essential oil was affected by rootstock type. Fruits from trees grafted on Flying dragon showed a darker and more intense green color, the highest values of TSS and lower percentage of weight loss.

Nitric oxide improves the effect of 1-methylcyclopropene extending the tomato (Lycopersicum esculentum L.) fruit postharvest life

Tomato fruit ripening and postharvest display a complex net of metabolic pathways, which are controlled by different signaling molecules and hormones that coordinate this physiological process. The inhibition of the ethylene action with 1-methylcyclopropene (1-MCP) has proved to be an excellent tool for maintaining fruit quality during postharvest. Along with these findings, nitric oxide (NO) demonstrated different effects on several species in fruit postharvest. The aim of this work was to evaluate the joint effect of 1-MCP and a NO donor (S-nitrosoglutathione, GSNO) during tomato postharvest at 23 °C. Breaker tomatoes were harvested from a local grower and divided in the following treatments: untreated, 1 mM GSNO, 0.5 μL L−1 of 1-MCP, and the combination of 1 mM GSNO + 0.5 μL L−1 1-MCP. Fruit was stored at 23 °C and analyzed after 5 and 10 d. According to the results, the combination of 1-MCP and the NO donor delayed fruit softening at days 5 and 10, reduced the ethylene synthesis significantly at day 5 and elevated the respiration rate at 10 d, compared to the individual treatments of 1-MCP and GSNO alone. However, the solely application of 1-MCP, independently from the addition of GSNO, showed a strong effect in the rise of the total titratable acidity content, together with the citric acid content. 1-MCP also up-regulated the CAT, SOD and POD activities at 5 and 10 d after harvest. These findings may suggest that some fruit quality parameters in tomato postharvest are controlled by ethylene, while others need the coordination of nitric oxide as a signal molecule.

Comparison of bacterial diversity in traditionally homemade paocai and Chinese spicy cabbage

This study aimed to investigate bacterial diversity in paocai and Chinese spicy cabbage and compare the microbial communities using high-throughput sequencing. Bacteria representing 26 phyla, 480 genera and 338 species were observed in these Chinese fermented vegetables. Firmicutes and Proteobacteria were the main phyla observed in both paocai and Chinese spicy cabbage. Additionally, Lactobacillus, Pediococcus, Serratia, Stenotrophomonas and Weissella were the major genera observed in both paocai and Chinese spicy cabbage. Overall, the relative abundances of Lactobacillus, Pediococcus and Weissella in Chinese spicy cabbage were much higher than those in paocai, but the proportions of Stenotrophomonas and Serratia in Chinese spicy cabbage were less than those in paocai. The results showed that the composition of the microbial community in Chinese spicy cabbage was positively correlated with total titratable acidity (TA), lactic acid and acetic acid contents but was negatively correlated with salinity. In contrast, the composition of the microbial community in paocai was negatively correlated with TA, lactic acid and acetic acid contents but was positively correlated with salinity. This study provides insights into the relationship between bacterial profiles and environmental factors in Chinese spicy cabbage and paocai, and its findings will aid in guiding future research on fermented vegetables.

Use of kombucha consortium to transform soy whey into a novel functional beverage

Soy whey is a liquid by-product from tofu and soy protein manufacturing, and is usually discarded, leading to environmental pollution. This study investigated the feasibility of transforming soy whey into a novel functional beverage using kombucha consortium. Changes in chemical compositions and bioactivities were monitored during the fermentation. The fermentation induced a reduction in pH and increase in total titratable acid content after fermentation. The antioxidant capacity of kombucha-fermented soy whey (KFSW) was significantly enhanced, as assessed by DPPH scavenging ability, ABTS radical scavenging ability, ferric reducing antioxidant power and reducing power. Furthermore, KFSW showed antibacterial activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli. In addition, the fermentation produced new aroma-active volatiles, especially esters and higher aldehydes, which imparted fruity flavor to soy whey and improved its sensory quality. Therefore, kombucha-fermentation can transform soy whey into a novel functional beverage, which could add value to the soy process by-product.

Influence of storage environment, maturity stage and pre-storage disinfection treatments on tomato fruit quality during winter in KwaZulu-Natal, South Africa

The aim of this study was to explore influence of evaporative cooling (EC), pre-storage disinfection treatments and maturity stage at harvest on postharvest quality of tomato fruit. The tomato samples (Lycopersicon esculentum Mill. cv. Nemonetta) were harvested, stored for 28 days and data were collected every seven days. The pH, total titratable acidity (TTA), total soluble solids (TSS), firmness, colour, weight loss (PWL) and marketability percentage were analysed. The temperature difference between ambient storage and EC at the fan varied between 4 and 7°C, the relative humidity (RH) varied between 31 and 86%, while at different locations inside the EC it varied between 2-3°C and 5-8%, respectively. Maturity had significant influence on the overall quality of tomatoes. The pH value of green, pink and red tomato was 4.86 and 5.03. The TTA content, the TSS content significantly affected over the 14days of storage. TSS:TA was found to be in the range of 7.8-33.9. The EC storage shows a higher firmness and hue angle, when compared to the ambient conditions stored tomatoes. Compared to ambient storage, EC storage reduced the PWL by 7-10% over 30days, while ambient storage took 15days. EC storage and pre-storage treatments improved the shelf-life and marketability of tomatoes. However, variation in temperature and RH inside EC could affect the storability of the produce.

Biochemical contents of apple peel and flesh affect level of partial resistance to blue mold

Apple fruit contains a wide range of chemical compounds that may contribute to resistance against blue mold caused by Penicillium expansum. In the present study, contents of total titratable acidity, malic acid, total phenols and 10 individual phenolic compounds were quantified in peel and flesh fractions of both control and blue mold-inoculated fruits of 24 apple cultivars. In addition to the significant variation among cultivars in terms of all quantified compounds, correlation analysis revealed a significant impact of total phenols and individual phenols like flavonols and procyanidins B2 in the peel fraction, on blue mold resistance in the inoculated fruits. Multivariate analyses on data for chemical compounds in peel tissue of inoculated fruits, could also separate resistant and susceptible cultivars. These findings can be useful in breeding programs since higher levels of phenolic compounds may indicate better resistance in apple cultivars.

A comparative study between a late-ripening mutant of citrus and its original line in fruit coloration, sugar and acid metabolism at all fruit maturation stage

Introduction. Fruit color is one of the important external traits that can be used to judge fruit maturation time in citrus. Mutants with different color are useful to study the regulating mechanism of color development. Materials and methods. A new seedless and late-maturing cultivar, ‘Huawan Wuzishatangju’ (HWWZSTJ) (Citrus reticulata Blanco), was selected from ‘Wuzishatangju’ (WZSTJ) through spontaneous bud mutation. Differences in fruit coloration, sugar and acidity contents of the two cultivars were investigated throughout fruit ripening. Results and discussion. Fruit of HWWZSTJ matured in late January to early February, more than 30 days later than WZSTJ. Results from RAPD analysis showed that HWWZSTJ originated from genetic mutation. The chlorophyll, carotenoid, total soluble solid (TSS) and total titratable acidity (TTA) contents of HWWZSTJ were affected by the mutation. Chlorophyll content in peel of HWWZSTJ was significantly higher than that of WZSTJ from November to mid-January while carotenoid content of HWWZSTJ peel was significantly higher than that of WZSTJ throughout fruit maturation. TTA content in HWWZSTJ was significantly higher than that in WZSTJ during early fruit ripening (from Nov. 29 to Dec. 9). Highest TSS (14.1%) was detected in the flesh of WZSTJ in mid-January compared to highest TSS (14.4%) of HWWZSTJ in early February. Conclusion. The mutation in HWWZSTJ detected by RAPD analysis, affected fruit coloration, sugar and acid metabolism, and might be responsible for other late-ripening phenotypes.

곰팡이 균주에 따른 누룩의 효소활성 및 약주 품질특성 비교

The enzymatic activity of Nuruk and the quality properties of Yakju were investigated according to different fungi. The fungi that were used in this study were Aspergillus kawachii KCCM 32819, Aspergillus niger KCCM 32005, Rhizopus japonicus KCCM 11604, Rhizopus oryzae KCCM 11272, Rhizopus oryzae KCCM 11273, Rhizopus oryzae KCCM 11276, and Mucor rouxii KCCM 60148. The study results are as follows. The saccharogenic power of Rhizopus oryzae KCCM 11272 Nuruk was the highest (3,647.72 SP/g) among all the samples. The α-amylase production and protease activities were highest (3.76 DU and 4.7 tyrosine mg/min, respectively) in the Rhizopus japonicus KCCM 11604 Nuruk. The pH levels of the Yakju made with commercial Nuruk and Rhizopus japonicus KCCM 11604 Nuruk were 4.14 and 4.07, respectively. The total titratable acid content of the Yakju made with Rhizopus oryzae KCCM 11273 Nuruk was the highest (0.56%) among all the samples. Rhizopus japonicus KCCM 11604 and Rhizopus oryzae KCCM 11272 had the highest ethanol yields (15.18% and 15.10%, respectively). In the sensory evaluation carried out in this study, the panel preferred the Yakju made with Rhizopus japonicus KCCM 11604 Nuruk. Overall, however, the panel did not like the Yakju made with Aspergillus niger KCCM 32005 Nuruk.

쌀 품종별 약주의 유기산, fusel oil 함량 및 항산화활성 비교

The organic acids, fuel oil contents and antioxidant activities of Yakju with the addition of rice varieties were investigated. The rice cultivars that were used in this study were Ilmi rice, Hopyung rice, Hopum rice, Hanarum rice, Anda rice and Indica rice. The study results are as follows: the pH values of Ilmi Yakju and Hanarum Yakju were 4.14 and 4.07, respectively, and those of the other Yakjus, 3.92~3.98. The total titratable acid content of the Yakju for which Indica rice was imported from Thailand was highest among the samples. The reducing sugars content of the Yakju for which Indica rice was used was higher than that of the other samples. The ethanol content of the Hanarum Yakju was higher than that of the other Yakjus, and the lowest ethanol content was found for the Indica Yakju. The major organic acid component of the Yakju was lactic acid. The total organic acid content was highest in the Indica rice Yakju. The amounts of the following main fusel oils were highest, in the following order: 2-butyl alcohol, 2-pentanol, N-propyl alcohol, acetaldehyde, ethyl acetate, methyl alcohol and 2-methyl-1-propyl alcohol. The DPPH free radical scavenging activity of the Indica rice Yakju was much higher than that of the Ilmi rice Yakju and the Hanarum rice Yakju. Also, the SOD activity of the Indica rice Yakju was strongest among all the samples. The total polyphenol content of the Indica rice Yakju was the highest among all the samples.

Effect of Fermentation Process on Nutritional Composition and Aflatoxins Concentration of <i>Doklu</i>, a Fermented Maize Based Food

Investigations were carried out to determine the influence of spontaneous fermentations as achieved at household level on the nutrients composition and aflatoxins concentration of maize during the processing into doklu, a fermented maize food product consumed in Cote d’Ivoire with legumes, soup and fried fish. Results showed that maize grains contained aflatoxin B1, G1 and G2 and that during fermentation all physicochemical parameters significantly (P ≤ 0.05) decreased except moisture and total titratable acidity contents which were significantly (P ≤ 0.05) increased. Fermentation also caused significant reduction in the concentration of total aflatoxins (72%), with the most important reduction in aflatoxin B1 (80%) after the soaking of maize grains. However, no aflatoxin was detected after 24 hours of fermentation until the final product was obtained. Despite the losses in some nutritional compounds, the fermented product, doklu, was found to have appreciable nutritional quality.

젖산농도별 주모에 따른 막걸리의 품질 특성

The quality characteristics of rice wine seed mash and rice wine made with different lactic acid concentrations were investigated. The pH decreased along with the lactic acid concentration. The total titratable acid content of the rice wine seed mash was lowest when 0.5% lactic acid was added, and the ethanol contents of the mash samples were not significant. The results of the measurement of the microorganism number, C (cell numbers of the total bacteria and the lactic acid bacteria), decreased along with the lactic acid concentrations of the mash samples. The yeast cell numbers of the rice wine seed mash samples according to the lactic acid concentrations were high (0.5, 0.3, 1.0, control, and 0.7%, respectively). The pH and total titratable acid levels of rice wine according to the lactic acid concentration were stable during fermentation, according to the increase in the amount of lactic acid. The organic acids in the rice wines were highest in the lactic acid. The rice wines to which lactic acid had been added had lower acetic acid contents than the control. Also, the acetic acid contents decreased along with the lactic acid concentrations, except in the rice wine treated with 1.0% lactic acid. The ethanol contents of the tested rice wines were not significant. All in all, in the sensory evaluation, the rice wines treated with 0.5 and 0.7% lactic acid scored higher than the other treatments.

LEAF SPRAY FERTILIZATION OF BORON AND ZINC ON PRODUCTIVITY AND FRUIT QUALITY OF JAPANESE PEAR TREE

The cultivation of fruit plants from temperate climate in tropical or subtropical regions can be a good income alternative for the producer. However, due to the little existent information about cultivation of those fruit plants, the producers use imported techniques of other producing areas, or even an association of practices used for other fruit plants, pointing out the leaf spray fertilization of micronutrients without appropriate scientific base. In this context, the objective of this study was to verify the effect of the leaf spray fertilization of B and Zn on productivity and fruit quality of Japanese pear tree. The experiment was conducted from 2004 to 2005, in Ilha Solteira, in northwestern Sao Paulo State-Brazil. The climate is, according to the Kopppen Classification, tropical wet and dry (Aw). The 'Okusankichi' cultivar, grafted on Pyrus communis L. rootstock was used as well as doses of 110 g.ha -1 of B and 250 g.ha -1 of Zn in each application. The treatments were: T1. water, T2. boric acid, T3. zinc sulfate, T4. T2 + T3, T5. boric acid + urea + citric acid + EDTA, T6. zinc sulfate + urea + citric acid + EDTA, T7. T5 + T6, T8. boric acid + urea + citric acid + EDTA + sodium molibdate + sulfur + calcium chloride, T9. zinc sulfate + urea + citric acid + EDTA + Fe sulfate + Mn sulfate + Mg sulfate and, T10. T8+T9. A randomized blocks design was used and the averages were compared by Tukey test. In the first crop the mixture of boric acid with quelating agents were efficient to supply B to the plants and zinc sulfate plus quelating agents were efficient to increase Zn leaf content. However, the productivity and the fruit quality were not influenced by the leaf spray of B and Zn. In the second crop the leaf content of B and Zn and the productivity were not influenced by the leaf spray; the boric acid and the zinc sulfate with or without quelating agents increased the contents of total soluble solids and, the boric acid with or without quelating agents increased the contents of total titratable acidity.

EFFECTS OF 1-METHYLCYCLOPROPENE ON INTERNAL BROWNING AND QUALITY IN COLD-STORED LOQUAT FRUIT

Internal browning (IB) and flesh leatheriness (mainly manifested as increased fruit firmness and decreased extractable juice rate) are major problems of loquat (Eriobotrya japonica Lindl.) fruit during cold storage. The effects of a postharvest application of 1-methylcyclopropene (1-MCP) on internal browning and quality in loquat fruit during storage at 5°C were investigated. Freshly harvested loquat fruit were exposed to 50 nl/L 1-MCP for 24 h at 20°C, and then stored for six weeks at 5°C. Changes in internal browning, polyphenol oxidase (PPO) activity, fruit firmness, extractable juice rate, total soluble solids (TSS) and total titratable acidity (TA) contents were monitored. The results showed that fruit internal browning was effectively controlled by 1-MCP for up to five weeks during storage at 5°C. Treatment with I-MCP inhibited PPO activity, which may account for inhibited internal browning. Increase in fruit firmness and decrease in extractable juice rate were significantly inhibited by 1-MCP treatment. Treatment with 1-MCP also arrested the decline in both TSS and TA contents. Thus, a postharvest application of I-MCP effectively reduced internal browning and maintained quality in cold-stored loquat fruit. These results suggest that 1-MCP may of commercial use to control internal browning and flesh leatheriness in loquat fruit during cold storage.

EFFECTS OF 1-METHYLCYCLOPENE ON FRUIT DECAY AND QUALITY IN CHINESE BAYBERRY

1-Methylcyclopene (1-MCP) prevents ethylene action and extends postharvest life of many fruits and vegetables. It has been shown that treatment concentration and temperature are two important factors affecting the efficacy of 1-MCP. Considering the very short shelf life of Chinese bayberry fruit at ambient temperature, this work was carried out to investigate the effects of 1-MCP treatment at low and high temperatures on fruit decay and quality in this fruit. The fruit (cv. 'Wuwei') were harvested at ripe stage and exposed to 0.5, 1.0, and 5 μL/L 1-MCP at 5°C for 12 h or at 20°C for 4 h. Following treatment, fruit were stored either at 0 °C for 12 days or at 20°C for 3 days. Treatment with 1-MCP at 5°C significantly reduced decay incidence during storage at both temperatures. The lowest concentration of 1-MCP was most effective in inhibiting fruit decay when stored at 0°C, having a decay index of 5% after 12 days of storage. In contrast, control fruit had a decay index of.15%. For fruit stored at 20°C after a treatment at 5 °C, 5 μL/L 1-MCP was most effective in reducing fruit decay. The decay index of those treated fruit was 12% at 3 days, compared with 20% in control fruit. In complete contrast, 1-MCP treatment at 20 °C led to increased fruit decay at either 0 or 20 °C storage. Treatment with 1-MCP at both temperatures maintained higher total soluble solids (TSS) content during storage at 0°C, however, no significant differences were observed among any of the 1-MCP treatments. There was no significant effect of 1-MCP on TSS content when the fruit were stored at 20°C. Total titratable acidity content was not significantly influenced by 1-MCP treatment. These results suggest that low temperature for 1-MCP treatment has the potential to extend the post-harvest life of Chinese bayberries by inhibiting fruit decay.

Quality of yellow passionfruit (Passiflora edulisSims f.flavicarpaDeg.) as affected by potassium nutrition

Introduction . The yellow passionfruit is consumed mainly as juice and is well accepted around the world. The nutritional state of the plant influences yield and fruit quality. We studied the particular effect of potassium nutrition on the quality of yellow passionfruit. Materials and methods . The experiments were conducted in a greenhouse at the Federal University of Vicosa, in Brazil, outlined in a randomized block design. The treatments were five concentrations of K [(1, 2, 4, 6 and 8) mmol·L–1] in a modified nutritive solution of Hoagland and Arnon. The experimental unit consisted of one plant in a 20-L pot containing washed sand. The plants were irrigated by a circulating hydroponic system. The nutrients were re-added to the solution based on its electric conductivity and on the K content in each solution. Results and discussion . The K supply increased yield and average fruit weight up to the concentration of (6.43 and 6.24) mmol·L–1, respectively, and linearly increased the number of seeds per fruit, thickness and relative water content of the pericarp and vitamin C content. The total titratable acid content increased according to a square equation, with the maximum point at 5.27 mmol K ·L–1. The pulp percentage, pH and total soluble solids content were not influenced by K doses. Conclusions . The increase in K supply promoted yield and fruit quality. At 90% of the maximum yield, the fruits had adequate quality traits.