Antioxidant and antimicrobial activities of bitter and sweet apricot (Prunus armeniaca L.) kernels

Abstract The present study describes the in vitro antimicrobial and antioxidant activity of methanol and water extracts of sweet and bitter apricot (Prunus armeniaca L.) kernels. The antioxidant properties of apricot kernels were evaluated by determining radical scavenging power, lipid peroxidation inhibition activity and total phenol content measured with a DPPH test, the thiocyanate method and the Folin method, respectively. In contrast to extracts of the bitter kernels, both the water and methanol extracts of sweet kernels have antioxidant potential. The highest percent inhibition of lipid peroxidation (69%) and total phenolic content (7.9 ± 0.2 µg/mL) were detected in the methanol extract of sweet kernels (Hasanbey) and in the water extract of the same cultivar, respectively. The antimicrobial activities of the above extracts were also tested against human pathogenic microorganisms using a disc-diffusion method, and the minimal inhibitory concentration (MIC) values of each active extract were determined. The most effective antibacterial activity was observed in the methanol and water extracts of bitter kernels and in the methanol extract of sweet kernels against the Gram-positive bacteria Staphylococcus aureus. Additionally, the methanol extracts of the bitter kernels were very potent against the Gram-negative bacteria Escherichia coli (0.312 mg/mL MIC value). Significant anti-candida activity was also observed with the methanol extract of bitter apricot kernels against Candida albicans, consisting of a 14 mm in diameter of inhibition zone and a 0.625 mg/mL MIC value.

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.

Osmotic dehydration of sweet potato (Ipomoea batatas) in ternary solutions

The aim of this work was to evaluate the osmotic dehydration of sweet potato (Ipomoea batatas) using hypertonic sucrose solutions, with or without NaCl, at three different concentrations, at 40 °C. Highest water losses were obtained when the mixture of sucrose and NaCl was used. The addition of NaCl to osmotic solutions increases the driving force of the process and it is verified that the osmotic dehydration process is mainly influenced by changes in NaCl concentration, but the positive effect of the salt-sucrose interaction on soluble solids also determined the decrease of solid gain when solutes were at maximum concentrations. Mass transfer kinetics were modeled according to Peleg, Fick and Page's equations, which presented good fittings of the experimental data. Peleg's equation and Page's model presented the best fitting and showed excellent predictive capacity for water loss and salt gain data. The effective diffusivity determined using Fick's Second Law applied to slice geometry was found to be in the range from 3.82 x 10-11 to 7.46 x 10-11 m²/s for water loss and from 1.18 x 10-10 to 3.38 x 10-11 m²/s for solid gain.

Psychophysical estimation of acid intensity and determination of sweet-acid interaction in a fish paste containing glycerol

In a fish paste made with cooked Brazilian flathead (Percophis brasiliensis), glycerol (17%), sodium chloride (1.5%) and potassium sorbate (0.1%) the following acid percentages: 0.2; 0.4; 0.6; 0.8, 1 and 1.5% w/w were incorporated to determine the relationship between added acetic acid and the sensorially perceived intensity, and the effects of the combination of sweet-acid tastes. Tests for paired comparison, ranking and structured verbal scales for sweet and acid attributes and psychophysical test were carried out. There was a perceptible difference among samples for differences of 0.4 units of acid concentration. Samples indicated as sweeter by 89.47% of the judges were those containing a lesser acid concentration. A reduction in glycerol sweetness when increasing acid levels was observed. Acetic acid reduced the sweetness of glycerol and inversely glycerol reduced the acidity of acetic acid. The data obtained with the magnitude estimation test agree with Steven's law.

Evaluation of the quality of a molded sweet biscuit enriched with okara flour

The objective of this research was to test the addition of soymilk residue, also known as okara, to a molded sweet biscuit (MSB). The okara was provided by two soymilk producing companies whose production systems are based on hot disintegration of decorticated (company B) or non-decorticated (company A) soybeans and separation of the soymilk. Okaras A and B were dehydrated in a flash dryer and then ground to a flour (< 200 mesh). The okara flours showed high protein (35 g.100 g-1 dwb), lipid (17 g.100 g-1 dwb), and fiber (17 to 21 g.100 g-1 dwb) contents. The water holding capacity, protein solubility, emulsifying capacity, emulsion stability and isoflavone contents found in flour A were significantly higher (p < 0.05) than in flour B. The formulation of MSB, replacing 30% (w/w) of the wheat flour with okara flour was tested. The results of the physical measurements, brittleness and water activity of the MSB with flours A and B did not differ significantly (p < 0.05) from those of the standard. The color, flavor and overall quality of the MSB with 30% of okara flour B did not differ significantly from those of the standard biscuit, demonstrating its potential for application in confectionery products.

Quality of yellow passion fruit stored under refrigeration and controlled atmosphere

In this study, it was evaluated the quality of yellow passion fruits stored under refrigeration and controlled atmospheres of different composition aiming to extend the postharvest life of the fruits. The characteristics of skin color, appearance, mass loss, as well as the chemical quality of the juice of yellow passion fruits stored at: 21% O2 plus 0.03% CO2; 1% O2 plus 0.03% CO2; 5% O2 plus 0.03% CO2; 12% O2 plus 5% CO2; and 5% O2 plus 15% CO2, with 1 control treatment (refrigeration at 13 ºC and 90% UR) were determined. The analyses were performed before and after 30 days of storage and after removing the controlled atmospheres and storage for 9 days under refrigeration at ambient atmosphere. The data were interpreted by simple statistical analysis using the test by confidence intervals with 95% of probability. It was concluded that the application of atmospheres with low oxygen concentration and high carbon dioxide level minimized quality losses. At atmosphere with 5% O2 and 15% CO2, it was observed the lowest color change indexes and mass loss, and also the smallest decrease in acidity, soluble solids content, vitamin C, reducing sugars, and total soluble sugars.

Yield of albedo flour and pectin content in the rind of yellow passion fruit

In this study, it was evaluated the influence of different shapes, sizes, and maturation stages on the yield of albedo flour and pectin content of yellow passion fruit rinds. Random samples of 40 fruits were used, and the data were compared using significance intervals at 5%. Weight, skin color, fruit size and shape, pulp yield, mesocarp thickness, amount of epicarp and mesocarp, moisture content, and pectin yield were determined. The maturation stages were defined according to measurements of the yellow color of the skin. The shape and size patterns were defined according to the length/width ratio (equatorial diameter) of fruits. It was found that the epicarp thickness was not correlated to fruit shape and size, but it was thicker in ripe fruits. The mesocarp was thiner in small ripe fruits, but it did not change with fruit shape. Pulp yield was higher in ripe fruits, and it was not influenced by shape and size of fruits. It was concluded that the content of albedo flour can account for 3.9% of the weight of processed fruits, whereas the amount of pectin powder can account for up to 0.9% of the fruit weight.

Bioactive compounds and antioxidant activity in fruits of clone and ungrafted genotypes of yellow mombin tree

Yellow mombin is a fruit tree that grows spontaneously in the Semi-Arid Northeastern Brazil. Its fruits are still extractively exploited. The pulp of yellow mombin fruit stands out regarding the commercial aspect due to the characteristic flavor and aroma felt when consumed in diverse ways. This study aimed to evaluate the presence of bioactive compounds, total extractable polyphenols, and antioxidant activity of yellow mombin fruits (Spondias mombin, L.), from clone and ungrafted genotypes. The fruits were harvested at commercial maturity from twelve yellow mombin tree genotypes from an experimental orchard located at the municipality of Joao Pessoa, Paraíba, Brazil, and evaluated for chlorophyll, carotenoids, yellow flavonoids, total extractable polyphenols, and antioxidant activity, which was measured by the β-carotene/linoleic acid method. The antioxidant activity showed a percentage of inhibition of oxidation higher than 75% for all genotypes evaluated at the time of 120 minutes. The fruits from clone genotypes showed a higher percentage of antioxidant activity.

Citotoxicity of food dyes sunset yellow (E-110), bordeaux red (E-123), and tatrazine yellow (E-102) on Allium cepa L. root meristematic cells

The objective of this study was to evaluate the cytotoxic effect of the food dyes sunset yellow, bordeaux red, and tartrazine yellow on the cellular cycle of Allium cepa L. Each dye was evaluated at the doses of 0.4 and 4.0 mL, at the exposure times of 24 and 48 hours in root tip cells of Allium cepa L. Slides were prepared and cells were analyzed during the whole cell cycle for cellular aberrations totaling 5,000 total cells for each dose evaluated. The mitotic index was calculated, and statistical analysis was performed using the Chi-squared test (p < 0.05). The results showed that the three dyes used under the evaluated doses and exposure times were cytotoxic to the cells of the system-test used. Further cytotoxicity studies should be conducted for additional results and a proper evaluation of the effect of these three dyes on a cellular level.

Quality characteristics of Moroccan sweet paprika (Capsicum annuum L.) at different sampling times

"La Niora" is a red pepper variety cultivated in Tadla Region (Morocco) which is used for manufacturing paprika after sun drying. The paprika quality (nutritional, chemical and microbiological) was evaluated immediately after milling, from September to December. Sampling time mainly affected paprika color and the total capsaicinoid and vitamin C contents. The commercial quality was acceptable and no aflatoxins were found, but the microbial load sometimes exceeded permitted levels.

Effect of hydrocolloids on the physicochemical characteristics of yellow mombin structured fruit

The technology for the production of restructured fruit with high contents of fruit pulp using hydrocolloids as binding agents has not been fully developed. This study evaluated the effect of mixtures of sodium alginate, low methoxy pectin, and gelatin on the characteristics of yellow mombin (Spondias mombin L.) fruit gels. The results of the central composite design showed that the models obtained, except for those of water activity and soluble solids, were predictive. Gelatin was the most important factor affecting firmness, pH, and the color parameters of the structured fruit pulp.

Influence of agro-ecological production areas on antioxidant activity, reducing sugar content, and selected phytonutrients of orange-fleshed sweet potato cultivars

Sweet potato is an important staple, and it is mainly known for its contribution of β-carotene in human diet. The effects of cultivar and habitat on this pigment and other nutritional characteristics of the crop still require investigation. In this study, three locally bred cultivars of sweet potato, two of which are orange-fleshed, were grown in three different agro-ecological areas to determine soluble sugar content, β-carotene, and total antioxidants of roots. In addition antioxidant activity, total carotenoids, and chlorophyll content were determined in edible leaves. Reducing sugars, β-carotene, total antioxidants capacity, total carotenoids, and chlorophyll content were significantly affected by environmental conditions. The location at lower altitude and closer to the coastline showed high evapotranspiration, thus reducing sugar content, antioxidant activity, and phytonutrients in both storage roots and leaves. Absence of water stress in agro-ecological locations further inland and at higher altitudes was associated with an increase in these compounds. Free radical scavenging activity of DPPH was higher in the storage roots (610.49 µmoles TE/100g) than in the leaves (426.06 µmoles TE/100g); nevertheless, opposite results were found for the ferric ion reducing activity (FRAP). The deep orange-fleshed cultivar A45 contained high β-carotene (15 mg/100g), which is enough to meet RDA for vitamin A. There is evidence of agro-ecological effect on sweet potato nutritional value.

Composition and color stability of anthocyanin-based extract from purple sweet potato

AbstractPurple sweet potato (PSP) can provide products with attractive color besides nutritious benefits in food processing. So, the compositions and color stability of an aqueous anthocyanin-based PSP extract were investigated in order to promote its wide use in food industry. PSP anthocyanins were extracted with water, and nine individual anthocyanins (48.72 ug mL–1 in total, 24.36 mg/100 g fresh PSP in yield) were found by HPLC analysis. The PSP extract also contained 17.11 mg mL–1 of protein, 0.44 mg mL–1 of dietary fiber, 2.82 mg mL–1 of reducing sugars, 4.02 ug mL–1 of Se, 54.21 ug mL–1 of Ca and 60.83 ug mL–1 of Mg. Changes in color and stability of the PSP extract, as affected by pH, heat, light and extraction process, were further evaluated. Results indicated that PSP anthocyanins had good stability at pH 2.0-6.0, while the color of PSP extract kept stable during 30 days of storage at 20 °C in dark. Both UV and fluorescent exposure weakened the color stability of PSP extract and UV showed a more drastic effect in comparison. A steaming pretreatment of fresh PSP is beneficial to the color stability.

Stability of gluten free sweet biscuit elaborated with rice bran, broken rice and okara

Abstract A challenge to the food sector has been the development of new products incorporating co-products from the food processing industry with minimal impact on their pre-determined structures and adding nutritional quality. In order to add value and develop alternatives for the use of co-products generated during the agroindustrial processing, this work aimed to study the stability of gluten-free sweet biscuits developed with soybean okara, rice bran and broken rice. The formulations were elaborated with increasing percentages of these ingredients and compared with the standard (commercial sweet biscuit) for ten months. The analyses were: weight, diameters (internal and external), thickness, specific volume, instrumental parameters of color, texture, scanning electron microscopy, water activity, proximal composition and isoflavones. The experimental sweet biscuits had characteristics of color, weight, volume and diameters (internal and external) very similar to the commercial, whereas texture, lipids and energy value decreased, and aw, moisture and protein increased during storage. The sweet biscuits showed the same stability when compared to the standard, and the