Starch edible coating of papaya: effect on sensory characteristics

The coating of papayas with Cassava Starch (CS) and carboxymethyl starch (CMS) is an alternative to extend the shelf life of these fruits. This study evaluated the effect of the three different levels of CS and CMS (1, 3, and 5%) on sensory characteristics of papayas during storage. Nine selected and trained assessors evaluated 13 sensory attributes using the Multiple Comparison Test. The appearance and flavor attributes of the papayas treated with CS and CMS were compared to the control or reference sample (R - fruit without coating) using a nine-point scale, which varied from 1: less intense than R; 5: equal to R; 9: more intense than R. The samples were coded with three digit numbers and evaluated with repetition by a panel of assessors. In general, appearance was more affected by the coatings than flavor. Fruits coated with 3 and 5% of both coatings kept the green color longer than the other coating’s concentrations, and at 5% the color of the fruits was less uniform on the last evaluation day. The 3 and 5% CS coating gave greater brightness to the fruits. 5% CMS favored the presence of fungi and damaged the fruit surface at the 14th day of storage. The CS coating at 5% presented peeled surface during all experimental time. Changes in fruits’ flavor were perceived at the 12th and 14th days of storage. A less characteristic flavor and a bitter taste were noticed in the fruits coated with CS and CMS at 5% at the 12th day of storage.

Effect of addition of different hydrocolloids on pasting, thermal, and rheological properties of cassava starch

Starches and gums are hydrocolloids frequently used in food systems to provide proper texture, moisture, and water mobility. Starch-gum interaction in food systems can change the starch granule swelling and its gelatinization and rheological properties. In this study, the effect of the addition of xanthan gum (XG), sodium carboxymethyl cellulose (SCMC), and carrageenan (CAR) at the concentrations of the 0.15, 0.25, 0.35 and 0.45% (w/v) on the pasting, thermal, and rheological properties of cassava starch was studied. The swelling power (SP) and the scanning electron microscopy (SEM) of the starch gels were also evaluated. The results obtained showed that xanthan gum (XG) had a strong interaction with the cassava starch penetrating between starch granules causing increase in pasting viscosities, SP, storage and loss (G', and G", respectively) modulus and reduction in the setback of the starch; sodium carboxymethyl cellulose (SCMC) greatly increased the pasting viscosities, the SP, and the storage and loss (G', and G", respectively) modulus of the starch-mixtures, mainly due to its greater capacity to hold water and not due to the interaction with cassava starch. Carrageenan (CAR) did not change any of the starch properties since there was no interaction between this gum and cassava starch at the concentrations used.

Changes in physical properties of extruded sour cassava starch and quinoa flour blend snacks

Given the broad acceptance of sour cassava starch biscuits in Brazil and the nutritional quality of quinoa flour, this study aimed to evaluate the effect of extrusion temperature, screw speed, moisture, and amount of quinoa flour on the physical properties of puffed snacks. Extrusion process was carried out using a single-screw extruder in a factorial central composite design with four factors. Effects of moisture and amount of quinoa flour on the expansion index and specific volume of snacks were observed. There was a pronounced increase in water solubility index of blends with the extrusion process with significant effects of all process parameters on the WSI. Higher water absorption index (WAI) was observed under high temperature, low moisture, and lower quinoa flour amount. Temperature and amount of quinoa flour influenced the color of the snacks. A positive quadratic effect of quinoa flour on hardness of products was observed. Blends of sour cassava starch and quinoa flour have good potential for use as raw material in production of extruded snacks with good physical properties.

Inactivation of E. coli and B. subtilis spores in ozonized cassava starch

In the present study, the efficacy of ozone inactivation of B. subtilis spores and E. coli in cassava starch was evaluated. Cassava starch with 18 and 30% moisture content was processed with ozone at concentrations of 40-118 ppm and exposure times of 15-120 minutes. The processing at 113 ppm/120 minutes (maximum exposure level to ozone evaluated) at 18% of moisture content did not cause significant reduction of B. subtilis spores and caused the reduction of only 2 decimal of E. coli. On the other hand, when the ozonation process was carried out for 120 minutes at 30% of moisture content, 3.6 decimal reduction of B. subtilis was achieved at 40 ppm of ozone and total B. subtilis load reduction (>5 log cycles) was observed at 118 ppm of ozone. Similarly, total E. coli load reduction (>7 log cycles) was achieved at 40 ppm of ozone exposure for 60 minutes. Therefore, the results indicate that the ozone efficacy against microorganisms in cassava starch was mainly dependent on the sample moisture content and to ozone concentration and exposure time. Moreover, it was observed that ozone is a promising technology to reduce microbial counts in dried food.

Effects of processing on physical properties of extruded snacks with blends of sour cassava starch and flaxseed flour

The opportunity to supplement common cassava biscuits with a product of higher nutritional value meets consumer expectations. In this work it was studied the effects of process parameters and flaxseed addition on physical properties of expanded snacks. Extrusion process was carried out using a single screw extruder in a factorial central composite rotatable design with four factors: flaxseed flour percentage (0-20%), moisture (12-20%), extrusion temperature (90-130 °C) and screw speed (190-270). The effect of extrusion variables was investigated in terms of expansion index, specific volume, water absorption index, water solubility index, color parameters (L*, a* ,b*) and hardness. The data analysis showed that variable parameters of the extrusion process and flaxseed flour affected physical properties of puffed snacks. Among the experimental conditions used in the present study, expanded snack products with good physical properties can be obtained under the conditions of 10% flaxseed flour, 230 rpm screw speed, temperature of 90 °C and moisture of 12%.

The effect of acid hydrolysis on the technological functional properties of pinhão (Araucaria brasiliensis) starch

Technological functional properties of native and acid-thinned pinhão (seeds of Araucária angustifolia, Brazilian pine) starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 ºC, 6 hours) and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days), paste freezing and thawing stability (after six freezing and thawing cycles), swelling power, and solubility. The results of light transmittance (%) of pastes of native and acid-thinned pinhão starches was higher (lower tendency to retrogradation) than that obtained for corn starches after similar storage period. Native pinhão starch (NPS) presented lower syneresis than native corn starch (NCS) when submitted to freeze-thaw cycles. The acid hydrolysis increased the syneresis of the two native varieties under storage at 5 ºC and after freezing and thawing cycles. The solubility of NPS was lower than that of native corn starch at 25, 50, and 70 ºC. However, for the acid-thinned pinhão starch (APS), this property was significantly higher (p < 0.05) when compared to that of acid-thinned corn starch (ACS). From the results obtained, it can be said that the acid treatment was efficient in producing a potential fat substitute from pinhão starch variety, but this ability must be further investigated.

Proteins of Bacuri almonds: nutritional value and in vivo digestibility

Bacuri (Scheelea phalerata Mart.) is a type of palm fruit tree widely distributed in the Brazilian Cerrado. The objective of this paper was to study the almonds of bacuri, in their form in natura and processed, focusing on their nutritional value through the profile of amino acids, anti-nutritional factors and in vivo digestibility. Raw and toasted samples of the almond presented a high level of proteins and fiber. Proteins of raw bacuri almond showed no limiting amino acid when compared to the ones recommended by FAO/WHO, and histidine was the most limiting essential amino acid in the toasted almonds. The almond of bacuri does not present anti- nutritional factors. In an assay with rats fed with control (casein), tests (bacuri almond flours) and aproteic diets, we verified the quantity of ration ingested and body weight gain, determining the urinary and metabolic nitrogen. Rats treated with the test diets presented inferior values of True Digestibility (DV), (82.9 and 72.3%, respectively for the raw and toasted almonds) when compared to the control group (92.3%). The raw bacuri almond presented a superior nutritional value to the one found in the toasted almond.

Resistant starch in cassava products

Found in different foods, starch is the most important source of carbohydrates in the diet. Some factors present in starchy foods influence the rate at which the starch is hydrolyzed and absorbed in vivo. Due the importance of cassava products in Brazilian diet, the objective of this study was to analyze total starch, resistant starch, and digestible starch contents in commercial cassava products. Thirty three commercial cassava products from different brands, classifications, and origin were analyzed. The method used for determination of resistant starch consisted of an enzymatic process to calculate the final content of resistant starch considering the concentration of glucose released and analyzed. The results showed significant differences between the products. Among the flours and seasoned flours analyzed, the highest levels of resistant starch were observed in the flour from Bahia state (2.21%) and the seasoned flour from Paraná state (1.93%). Starch, tapioca, and sago showed levels of resistant starch ranging from 0.56 to 1.1%. The cassava products analyzed can be considered good sources of resistant starch; which make them beneficial products to the gastrointestinal tract.

Characterization, physicochemical stability, and evaluation of in vitro digestibility of solid lipid microparticles produced with palm kernel oil and tristearin

Solid lipid particles have been investigated by food researchers due to their ability to enhance the incorporation and bioavailability of lipophilic bioactives in aqueous formulations. The objectives of this study were to evaluate the physicochemical stability and digestibility of lipid microparticles produced with tristearin and palm kernel oil. The motivation for conducting this study was the fact that mixing lipids can prevent the expulsion of the bioactive from the lipid core and enhance the digestibility of lipid structures. The lipid microparticles containing different palm kernel oil contents were stable after 60 days of storage according to the particle size and zeta potential data. Their calorimetric behavior indicated that they were composed of a very heterogeneous lipid matrix. Lipid microparticles were stable under various conditions of ionic strength, sugar concentration, temperature, and pH. Digestibility assays indicated no differences in the release of free fatty acids, which was approximately 30% in all analises. The in vitro digestibility tests showed that the amount of palm kernel in the particles did not affect the percentage of lipolysis, probably due to the high amount of surfactants used and/or the solid state of the microparticles.

Particle size and cholesterol content of a mayonnaise formulated by OSA-modified potato starch

Egg yolk was partially replaced (0, 25, 50, 75, and 100%) with octenyl succinic anhydride (OSA)-modified potato starch in a reduced-fat mayonnaise formulation to curtail the problems associated with high cholesterol and induced allergic reactions. The physicochemical properties included parameters such as: pH, fat content, and emulsion stability of the formulations analyzed. The samples with 75% and 100% egg yolk substitute showed the maximum emulsion stability (>95% after two of months storage), and they were selected according to cholesterol content, particle size distributions, dynamic rheological properties, microstructure, and sensory characteristic. A significant reduction (84-97%) in the cholesterol content was observed in the selected samples. Particle size analysis showed that by increasing the amount of OSA starch, the oil droplets with the peak size of 70 µm engulfed by this compound became larger. The rheological tests elucidated that in the absence of egg yolk, OSA starch may not result in a final product with consistent texture and that the best ratio of the two emulsifiers (OSA starch/egg yolk) to produce stable reduced-fat, low cholesterol mayonnaise is 75/25. The microscopic images confirmed the formation of a stable cohesive layer of starch surrounding the oil droplets emulsified in the samples selected.

Effect of different proportions of brea gum in the functional characteristics of wheat flour starch: impact on the physical quality of bread

The aim of this work was to study the changes induced by BG in the behaviour of wheat starch, and observe the influence of these variations on the quality of a basic white bread. The effect of four BG addition levels in the wheat flour functional characteristics (WAI, WSI, and pasting properties) and bread quality (physical parameters, crumb grain structure, moisture and hardness) was investigated. The highest levels of BG (1% and 2%) decreased the peak viscosity, and increased the stability and setback of the flour. This was due to a lower gelatinization of the starch granules, caused by a competition for water between the hydrocolloid and starch. These changes influenced the bread quality. The loaves added with 1% and 2% of BG presented smaller alveoli: this resulted in more compact, hard and less airy crumbs. Nevertheless, the moisture of the samples at 1% and 2% of added gum was higher than the control bread. However, the incorporation of BG at 0.5% did not affect the pasting parameters and bread quality, but increased moisture of crumb, so this concentration would be most recommended for baking, since higher humidity could favour the shelf- life of the product.

Effect of incorporation of nutraceutical capsule waste of safflower oil in the mechanical characteristics of corn starch films

Abstract Biodegradable films blends made of safflower oil nutraceutical capsules waste corn starch (20:4, 30:4, 40:4 and 50:4) were prepared. The objective of this study was to evaluate the influence of addition of different concentrations of safflower oil nutraceutical capsule waste in the mechanical properties (tensile strength, elongation at break, Young’s modulus) and thickness of corn starch films. A decrease in tensile strength and Young’s modulus and an increase in elongation at break were observed with the increase in the content of the nutraceutical capsule waste. The results showed that the blends of safflower oil capsules waste-corn starch films demonstrated promising characteristics to form biodegradable films with different mechanical characteristics.

Use of biofilm in the postharvest conservation of 'Pedro Sato' guava

This present work aimed to assess the effect of different concentrations of cassava starch, associated or not with prochloraz fungicide, on the postharvest conservation of 'Pedro Sato' guavas. Physiologically mature fruits were immersed in a solution of prochloraz (49.5 g/100 liters of water) for 5 min. Fruit treated with distilled water and air dried were used as control. They were immersed in cassava starch suspension at concentrations of 0, 20, 30 and 40 g/L, plus 0.5 mL/L of mineral oil. The fruits were stored at 21.0 ± 1.0 ºC and relative humidity of 85 ± 5%, for 12 days, and were examined at every three days. The combination of prochloraz and cassava starch resulted in delayed loss of firmness and yellowness and inhibited the incidence of lesions caused by Colletotrichum gloeosporioides during the 12 days of storage. Fruits treated with 40 g/L of starch, whether containing prochloraz or not, had unpleasant taste and odor, which suggests the occurrence of fermentation. Control fruits, with and without prochloraz, and those treated with starch with no prochloraz, had nearly 100% lesion occurrence within the 12 days. Starch suspension of 30 g/L, containing prochloraz, was the most effective in maintaining fruit quality.

Influence of the use of acids and films in post-harvest lychee conservation

Lychee (Litchi chinensis Sonn.) has a high commercial value; however, it has a short shelf-life because of its rapid pericarp browning. The objective of this study was to evaluate the shelf-life of 'Bengal' lychee fruits stored after treatment with hydrochloric acid and citric acid, associated with cassava starch and plastic packaging. Uniformly red pericarp fruits were submitted to treatments: 1-(immersion in citric acid 100 mM for 5 minutes + cassava starch 30 g L-1 for 5 minutes), 2-(immersion in hydrochloric acid 1 M for 2 minutes + starch cassava 30 g L-1 for 5 minutes), 3-(immersion in citric acid 100 mM for 5 minutes + polyvinyl chloride film (PVC, 14 µm thick)) and 4-(immersion in hydrochloric acid 1 M for 2 minutes + PVC film). During 20 days, the fruits were evaluated for mass loss, pericarp color, pH, soluble solids and titratable acidity, vitamin C of the pulp and pericarp and activities of polyphenol oxidase and peroxidase of the pericarp. The treatment with hydrochloric acid associated with PVC was the most effective in maintaining the red color of the pericarp for a period of 20 days and best preservation of the fruit. The cassava starch associated with citric acid, and hydrochloric acid did not reduce the mass loss and did not prevent the browning of lychee fruit pericarp.

Chemical, morphological, rheological and thermal properties of Solanum lycocarpum phosphorylated starches

The increasing need for starches with specific characteristics makes it important to study unconventional starches and their modifications in order to meet consumer demands. The aim of this work was to study physicochemical characteristics of native starch and phosphate starch of S. lycocarpum. Native starch was phosphated with sodium tripolyphosphate (5-11%) added with stirring. Chemical composition, morphology, density, binding ability to cold water, swelling power and solubility index, turbidity and syneresis, rheological and calorimetric properties were determined. Phosphorus was not detected in the native sample, but the phosphating process produced modified starches with phosphorus contents of 0.015, 0.092 and 0.397%, with the capacity of absorbing more water, either cold or hot. Rheological data showed the strong influence of phosphorus content on viscosity of phosphate starch, with lower pasting temperature and peak viscosity higher than those of native starch. Enthalpy was negatively correlated with the phosphorus content, requiring 9.7; 8.5; 8.1 and 6.4 kJ g-1 of energy for the transition from the amorphous to the crystalline state for the starch granules with phosphorus contents of 0; 0.015; 0.092 and 0.397%, respectively. Cluster analysis and principal component analysis showed that starches with 0.015 and 0.092% phosphorus have similar characteristics and are different from the others. Our results show that the characteristics of phosphate modified S. lycocarpum starch have optimal conditions to meet the demands of raw materials, which require greater consistency in stickiness, combined with low rates of retrogradation and syneresis.