Postharvest respiratory activity and changes in some chemical constituents during maturation of yellow mombin (Spondias mombin) fruit

Mature fruit from the yellow mombin (Spondias mombin) was monitored for its respiration activity. Mature green fruit from the yellow mombin was stored in closed glass chambers and the concentration of oxygen and carbon dioxide at the end of a six hour respiration period was determined. At the same interval of time, the lid of the chamber was opened for air renewal. The increase in carbon dioxide and decrease in oxygen concentration demonstrated that the fruit was climacteric. The maximum liberation of CO2 54.2 mL Kg-1 h-1 and maximum absorption of O2 49.0 mL Kg-1 h-1 occurred 186 hours after the harvest which, obviously, represented the optimum fruit quality after the senescence process started. The respiratory quotient of fruit at a climacteric maximum was 1.11 representing the oxidation of carbohydrates. Total soluble solids increased from 9.1 °Brix (initial) to 13.7 °Brix (climacteric maximum) during maturation, while the total number of acids in the fruit decreased during maturation i.e. from 1.55% initially to 1.40% at pre-climacteric, 1.0% at climacteric maximum and 0.8% in the post-climacteric stage. A similar behaviour was observed in the case of ascorbic acid. There was a continuous decrease in chlorophyll and a continuous increase in the carotenoid content of fruit during maturation.

Physico-chemical characterization and bioactive compounds of blackberry fruits (Rubus sp.) grown in Brazil

Five blackberry cultivars (Rubus sp.) were evaluated for antioxidant capacity, bioactive compounds and composition. Ascorbic acid levels, consisting of dehydro-ascorbic acid, ranged from 9.8 to 21.4 mg.100 g-1 fresh weight. Cyanidin (66 to 80% of total flavonoids), epicatechin, quercetin and traces of kaempferol were the main flavonoids found in all cultivars. The five cultivars presented high antioxidant capacity in the β-carotene/linoleic acid system, with inhibition similar to the synthetic antioxidant BHT, at a 50 µM concentration. Caingangue cultivar presented high vitamin C and total phenolics content, while Guarani had the highest cyanidin, total anthocyanin and total flavonoids levels and also the highest antioxidant capacity. These cultivars also presented good TSS/TA ratios. From the data, at a quantitative level, blackberry can be considered a good source of bioactive compounds, as well as potentially beneficial to human health.

Lactobacillus plantarum strains isolated from naturally fermented sausages and their technological properties for application as starter cultures

In the present study, technological properties of L. plantarum strains isolated from naturally fermented sausages manufactured in the South region of Brazil were investigated in order to obtain a starter culture. The technological properties evaluated were the following: ability to growth at different pH values, at different temperatures, in different salt concentrations and in the presence of commercial curing salt, fast production of acid, determination of D - and L - lactic acid; nitrate reductase activity; antagonistic activity and stability of the isolated cultures after fermentation, concentration, and freeze-drying process. The isolated strains showed effectiveness to improve technological properties as starter cultures.

Quality of minimally processed guava with different types of cut, sanification and packing

The purpose of this project was to evaluate the sanitization effect on the quality of minimally processed guava. Initially, research was carried out with consumers in a supermarket to verify preferences of packaging for guava. Following this, the guava cv. Paluma underwent two sanitization sequences using dehydrated sodium dichloroisocyanurate compound, in 50 ppm concentration, sanitization prior to (S1) and after (S2) being cut; removal of excess water; conditioning in PET packaging and PSPVC and storage at 3 ºC ± 1 ºC. Physicochemical analysis - [pH, total soluble solids (SST), total labeled acidity (ATT), ascorbic acid (AA), total sugars (AT) and reducers (AR)], textural sensorial and microbiological analyses were used to monitor the quality of the products. The consumers preferred the guava cut in halves with pulp and packed in PET, although this packaging promoted condensation of water vapor on the inner surface of the lid, compromising the appearance of the product. The two sanitization sequences and the two kinds of packaging did not significantly affect the pH, SST, ATT, SST/ATT, texture and AA values. The AT and AR tenors increased significantly in the MP guavas stored in the PSPVC package. Both sanitizations were efficient in the bacterial control of the indicators of the hygienicsanitary conditions, although the S1 sanitization proved to be more efficient in the control of autochthonous aerobic microbiota (aerobic mesophylic microorganisms). It can be concluded that guava cv. Paluma packed in PSPVC can be conserved for 6 days when stored at 3 ºC.

Carbohydrate composition of ripe pineapple (cv. perola) and the glycemic response in humans

Brazil is the third largest producer of pineapple (Ananas comosus) and the market for fresh pineapple is sustained by the Hawaii and Perola cultivars. In this work the Perola cultivar was divided into three main parts, shell, core and pulp, for characterization. Moisture in the pulp was higher (between 10 and 15%) than in the shell and core. The amount of protein was higher in the core (35%) than in the pulp and shell. Perola contained relatively low concentrations of total ascorbic acid in the edible parts, although higher levels of ascorbic acid in the shell. Citric acid corresponded to almost 60% of the total organic acids. The total soluble sugars [~7-12% (FW)] were predominantly sucrose, fructose and glucose. The core had almost twice as much total sugar (12%) than the pulp (6.8%). The amount of insoluble dietary fiber was around 1%, and the soluble fiber was less than 0.1%. The pulp showed the highest concentration of polyphenols (0.49%) and antioxidant activity (33 µmol.g-1) out of the parts. The consumption of the pineapple pulp or core produced a high glycemic index (~93%), but considering the glycemic load, this fruit can be considered as low dietary.

Chemical composition of five loquat cultivars planted in Brazil

Loquat is a fruit with high market value cultivated in Southeast Brazil. Despite of this, there are little details about its quality characteristics. Fruits from five loquat cultivars, developed using genetic breeding, were analyzed to assess their compositional traits. The cultivars Centenária, Mizuho, Mizumo, Néctar de Cristal and Mizauto were selected based on their high productivity and resistance to diseases. Soluble sugars, organic acids, and carotenoids were quantified using liquid chromatography. The cultivar (cv.) with the highest total sugar concentration was Mizumo and the lowest concentration was found in Centenária. The main sugar detected was sucrose, and the malic acid was the major organic acid. Ascorbic acid was detected in small amounts. The total dietary fiber contents were almost the same in all cultivars. The major carotenoids detected were β-carotene and β-cryptoxanthin, except for the cultivar Nectar de Cristal, a white pulp loquat. These results contribute to the knowledge about de physiology of loquat fruit, an interesting raw material due to its nutritional and sensorial characteristics. Furthermore, the results obtained could help to identify the most appropriate use of the loquats with different attributes either for consumption in natura or for industrial processing.

Stability studies and shelf life estimation of a soy-based dessert

This work is aimed at evaluating the physicochemical, physical, chromatic, microbiological, and sensorial stability of a non-dairy dessert elaborated with soy, guava juice, and oligofructose for 60 days at refrigerated storage as well as to estimate its shelf life time. The titrable acidity, pH, instrumental color, water activity, ascorbic acid, and physical stability were measured. Panelists (n = 50) from the campus community used a hedonic scale to assess the acceptance, purchase intent, creaminess, flavor, taste, acidity, color, and overall appearance of the dessert during 60 days. The data showed that the parameters differed significantly (p < 0.05) from the initial time, and they could be fitted in mathematical equations with coefficient of determination above 71%, aiming to consider them suitable for prediction purposes. Creaminess and acceptance did not differ statistically in the 60-day period; taste, flavor, and acidity kept a suitable hedonic score during storage. Notwithstanding, the sample showed good physical stability against gravity and presented more than 15% of the Brazilian Daily Recommended Value of copper, iron, and ascorbic acid. The product shelf life estimation found was 79 days considering the overall acceptance, acceptance index and purchase intent.

Flavonoids, total phenolics and antioxidant capacity: comparison between commercial green tea preparations

The potential health benefits attributed to green tea and its catechins such as antioxidant effects, cancer chemoprevention, and weight loss have led to a huge increase of green tea products in the food market. The objectives of this work were to analyze and compare these products in terms of phenolic contents and in vitro antioxidant capacity including tea bags, dehydrated leaves, and ready-to-drink preparations after standardization of the infusion preparation procedure. Total phenolics content in 1 cup of the different teas varied from 90 to 341 mg of catechin equivalents, and the highest and the lowest values were both those of the ready-to-drink products. Infusions prepared from tea bags had contents varying from 96 to 201 mg.200 mL-1, and there were no significant differences among batches. The DPPH radical scavenging and the Oxygen Radical Absorbing Capacities (ORAC) varied largely among the different tea preparations, from 23 to 131 mmoles of Trolox Equivalents (TE).200 mL-1 (DPPH), and from 1.2 to 5.1 mmoles of TE.200 mL-1 (ORAC), but again there were no differences among infusions or ready-to-drink commercial preparations. However, the antioxidant capacity of ready-to-drink products was partially due to the presence of other non-phenolic compounds such as ascorbic acid

Evaluation of antioxidants stability by thermal analysis and its protective effect in heated edible vegetable oil

In this work, through the use of thermal analysis techniques, the thermal stabilities of some antioxidants were investigated, in order to evaluate their resistance to thermal oxidation in oils, by heating canola vegetable oil, and to suggest that antioxidants would be more appropriate to increase the resistance of vegetable oils in the thermal degradation process in frying. The techniques used were: Thermal Gravimetric (TG) and Differential Scanning Calorimetry (DSC) analyses, as well as an allusion to a possible protective action of the vegetable oils, based on the thermal oxidation of canola vegetable oil in the laboratory under constant heating at 180 ºC/8 hours for 10 days. The studied antioxidants were: ascorbic acid, sorbic acid, citric acid, sodium erythorbate, BHT (3,5-di-tert-butyl-4-hydroxytoluene), BHA (2, 3-tert-butyl-4-methoxyphenol), TBHQ (tertiary butyl hydroquinone), PG (propyl gallate) - described as antioxidants by ANVISA and the FDA; and also the phytic acid antioxidant and the SAIB (sucrose acetate isobutyrate) additive, which is used in the food industry, in order to test its behavior as an antioxidant in vegetable oil. The following antioxidants: citric acid, sodium erythorbate, BHA, BHT, TBHQ and sorbic acid decompose at temperatures below 180 ºC, and therefore, have little protective action in vegetable oils undergoing frying processes. The antioxidants below: phytic acid, ascorbic acid and PG, are the most resistant and begin their decomposition processes at temperatures between 180 and 200 ºC. The thermal analytical techniques have also shown that the SAIB antioxidant is the most resistant to oxidative action, and it can be a useful choice in the thermal decomposition prevention of edible oils, improving stability regarding oxidative processes.

Application of mathematical models for the prediction of adsorption isotherms in solid mixture for mango powder refreshment

Solid mixtures for refreshment are already totally integrated to the Brazilian consumers' daily routine, because of their quick preparation method, yield and reasonable price - quite lower if compared to 'ready-to-drink' products or products for prompt consumption, what makes them economically more accessible to low-income populations. Within such a context, the aim of this work was to evaluate the physicochemical and mineral composition, as well as the hygroscopic behavior of four different brands of solid mixture for mango refreshment. The BET, GAB, Oswim and Henderson mathematical models were built through the adjustment of experimental data to the isotherms of adsorption. Results from the physiochemical evaluation showed that the solid mixtures for refreshments are considerable sources of ascorbic acid and reductor sugar; and regarding mineral compounds, they are significant sources of calcium, sodium and potassium. It was also verified that the solid mixtures for refreshments of the four studied brands are considered highly hygroscopic.

Changes in enzymes, phenolic compounds, tannins, and vitamin C in various stages of jambolan (Syzygium cumini Lamark) development

The physiological state of a fruit is closely related to ripening and climatic conditions during the growing period when the fruit undergo changes in color, texture, and flavor. The ripening of the fruit can involve a complex series of biochemical reactions with alteration in enzymes activities, phenols, tannins, and ascorbic acid. The activity of enzymes (carboximethylcellulase, polygalacturonase, and pectinlyase), the total concentration of phenolic compounds, condensed tannins, and vitamin C in five stages of maturation were studied. Significant changes were observed between the maturity stages. The phenolic compounds were higher at green stage (705.01 ± 7.41); tannins were higher at green/purple stage (699.45 ± 0.22). The results showed that the ascorbic acid levels of the pulp varied significantly from 50.81 ± 1.43 to 6.61 ± 1.04 mg.100 g-1 during maturation. The specific activity of pectin lyase was higher at green stage (1531.90 ± 5.83). The specific activity of polygalacturonase was higher at mature stage (1.83 ± 0.0018). The specific activity of carboximetilcelulose was higher at ripe mature stage (4.61 ± 0.0024). The low ascorbic acid content found in jambolan fruit indicates that this fruit is not a rich source of this nutrient; however, other characteristics can make jambolan products fit for human consumption.

Effect of holding period prior to storage on the chemical attributes of Starking Delicious apples during refrigerated storage

In this research, the effects of three different holding periods (6, 12 and 24 hours) prior to storage on the quality attributes of Starking Delicious apples were investigated during storage of 8 months at 0.5 ± 1.0 ºC. Changes in weight loss, flesh firmness, pH values, soluble dry matter amount, titratable acidity values, ascorbic acid contents, and total and reducing sugar content were determined. According to the results, the holding period showed statistically significant changes in the quality attributes of the apples (p < 0.05).

Assessment of lettuce quality during storage at low relative humidity using Global Stability Index methodology

During postharvest, lettuce is usually exposed to adverse conditions (e.g. low relative humidity) that reduce the vegetable quality. In order to evaluate its shelf life, a great number of quality attributes must be analyzed, which requires careful experimental design, and it is time consuming. In this study, the modified Global Stability Index method was applied to estimate the quality of butter lettuce at low relative humidity during storage discriminating three lettuce zones (internal, middle, and external). The results indicated that the most relevant attributes were: the external zone - relative water content, water content , ascorbic acid, and total mesophilic counts; middle zone - relative water content, water content, total chlorophyll, and ascorbic acid; internal zone - relative water content, bound water, water content, and total mesophilic counts. A mathematical model that takes into account the Global Stability Index and overall visual quality for each lettuce zone was proposed. Moreover, the Weibull distribution was applied to estimate the maximum vegetable storage time which was 5, 4, and 3 days for the internal, middle, and external zone, respectively. When analyzing the effect of storage time for each lettuce zone, all the indices evaluated in the external zone of lettuce presented significant differences (p < 0.05). For both, internal and middle zones, the attributes presented significant differences (p < 0.05), except for water content and total chlorophyll.

Synergistic and antimicrobial properties of commercial turmeric (Curcuma longa) essential oil against pathogenic bacteria

Several studies have shown the antimicrobial and antioxidant properties of turmeric (Curcuma longa), widely used in food industry as a colorant, among other functions. The aim of this study was to determine the antioxidant and antimicrobial properties of turmeric essential oil against pathogenic bacteria and to study the influence of the addition of ascorbic acid on the prevention of polyphenols oxidation. The commercial turmeric essential oil alone did not show bactericidal activity against the microorganisms studied, Listeria monocytogenes and Salmonella typhimurium, but when combined with ascorbic acid, it showed significant antibacterial activity. The highest antimicrobial activity of turmeric essential oil against Salmonella typhimurium was 15.0 ± 1.41 mm at the concentration of 2.30 mg.mL-1 of essential oil and 2.0 mg.mL-1 of ascorbic acid. With regard to Listeria monocytogenes, the largest zone of inhibition (13.7 ± 0.58 mm) was obtained at the same concentrations. The essential oil showed antioxidant activity of EC50 = 2094.172 µg.mL-1 for the DPPH radical scavenging method and 29% under the concentration of 1.667 mg.mL-1 for the β-carotene bleaching method.

Physicochemical and microbiological characteristics of minimally processed 'Champagne' oranges (Citrus reticulata × Citrus sinensis) in different packgings

The objective of this study was to investigate the influence of the level of minimal processing and modified atmosphere on the quality of 'Champagne' orange stored under refrigeration. The fruits were subjected to the following processing: a) whole fruit without flavedo; b) whole fruit without flavedo and albedo; and c) segmented into wedges and packed as follows: uncoated packaging (control); polyethylene film; PVC film; gelatin-based edible films (3%); and polyesthyrene translucent plastic container with a lid. The minimally processed oranges were stored at 5 ± 1°C for 8 days and were subjected to physicochemical and microbiological analyses every two days. Greater weight loss occurred in fruits without flavedo and segmented, uncoated, and coated with the edible gelatin film During storage, there was a slight increase in Total Soluble Solids (TSS) for the treatments with greater weight loss and reduction in acidity and ascorbic acid, regardless of the packaging type. The microbial counts did not exceed the acceptable limits in the treatments; however, higher counts were observed at the end of storage. The minimally processed fruit packed in lidded polystyrene containers and polyethylene and PVC films kept their overall fresh visual appearance with a few physicochemical and microbiological changes up to the 8th day of storage.