Physicochemical Properties of Grain and Starch from Kanihua (chenopodium Pallidicaule) Compared with Quinoa (chenopodium Quinoa) Originated from Peru

Kanihua and quinoa are closely related Andean grains that are unconventional starch sources. Starch was extracted from two kanihua and three quinoa genotypes and their physicochemical properties (proximate analysis, scanning electron microscopy, distribution and particle size, X-ray diffraction, FTIR, solubility, swelling power, pasting and thermal properties) were investigated. Kanihua and quinoa grains presented spherical shapes and regular sizes (1.05 - 1.30 mm). The starch granules show asymmetric monomodal distribution for all cases. Meanwhile, Sauter diameter values in kanihua were smaller (0.961 µm) than quinoa (1.099 µm). Regarding structure, all samples showed Type A polymorphism and similar FTIR spectra behavior. In addition, amilose content was around 11-14% and 8-12% for varieties of kanihua and quinoa respectively. Starch solubilities were less than 13%, and kanihua starches had less swelling power than quinoa starches. However, the maximum swelling power values were reached around 70 °C. The variety and type of grain influenced pasting properties, with an inverse relationship between the breakdown and setback values for the evaluated starches. Analyzing the thermal properties, gelatinization enthalpy and retrogradation were similar for all starches. Even though the kanihua and quinoa starches present similar structural characteristics, the pasting properties and swelling power were different. The insight into the morphological, thermal, and pasting properties of native Chenopodium starches could be helpful in the preparation and development of new food formulations

Impact of Ozone on the Rheological and Morphological Properties of Quinoa Starch

Native starch has limitations such as low water solubility and high viscosity. Ozone treatment is a green technique that can be used to modify starch by oxidation without generating waste. Quinoa starch suspensions (10wt%, db) were submitted to the modification process by the application of ozone at different times (OGT = 10, 20 and 30 min), with native starch as the control. Morphological, solubility in water (SW), swelling power (SP) and rheological characterizations were carried out to evaluate the properties of native and oxidized starches. SW values were lower (37.4%) and SP values were slightly lower (6.0%) for native starch and starch modified by 10 min of OGT, when compared to starches with 20 and 30 min of OGT. This indicates a weakening of the bonds in the crystalline region with the longest ozonation times influencing the swelling of the granules and allowing them to absorb water more easily. The rheological tests showed that all samples (5 g gelatinized starch/100 g) had pseudoplastic behavior, with increased pseudoplasticity, consistency index and apparent viscosity, with increasing OGT. The increase in rheological properties after ozone treatment can be attributed to the crosslinking effect. On the other hand, the increase in pseudoplasticity can be explained by the partial depolymerization of amorphous and crystalline lamellae compounds during starch oxidation. Frequency scanning sweep indicated that all samples exhibited weak gel behavior (storage modulus G'>G” loss modulus), without crossing of these moduli. Native starch had the highest G’ and G” values when compared to ozonized starches. No difference was observed in gelatinization temperature and granule morphology after ozone treatment. The differences in the flow and viscoelastic properties can be interesting for different applications, such as thickeners in food or cosmetics products

Estudo dos métodos para a medida da atividade de água.

A atividade de água é um dos parâmetros mais mportantes para a indústria de alimentos. Existem muitos métodos para a medida da atividade de água e cada um tem suas limitações. Foram analisados os diversos métodos existentes para a medida da atividade de água, considerando-se seu princípio de funcionamento, o manuseio do equipamento, o tempo para realização da medida, a faixa de medida, a calibração do equipamento, a repetibilidade e reprodutibilidade e o custo do equipamento. Foram comparados dados da atividade de água de soluções saturadas e insaturadas de sais e de soluções de ácido sulfúrico de várias referências. O objetivo foi uniformizar os padrões adotados nos diversos métodos de medida da atividade de água. Não apenas, são apresentados os modelos matemáticos de Brunauer, Emmett e Teller e o de Guggenheim, Anderson e De Boer, para aproximar isotermas de sorção, mas também, são analisadas as aplicações das medidas da atividade de água e isotermas de sorção de água em alimentos. Os melhores métodos existentes atualmente são o higrômetro eletrônico e o higrômetro de ponto de orvalho. A principal desvantagem desses métodos é seu custo elevado, o que os torna inacessíveis a uma parcela significativa da indústria de alimentos brasileira. Um novo método foi proposto para ser usado na indústria e deve reunir as características de rapidez suficiente e baixo custo.Water activity is one of the most important parameters for the food industry. There are many methods to measure water activity and each one of them has its handicaps. Several of the available methods to measure water activity were studied considering their technical details, handling of the equipment, measurement speed, measurement range, calibration of the equipment, repeatability and reproducibility and cost. Water activity data of saturated and unsaturated salt solutions and sulphuric acid solutions from various sources are compared. The purpose is to provide standards to be adopted by the different methods to measure water activity. The mathematical models of Brunauer, Emmett and Teller and Guggenheim, Anderson and De Boer for estimating sorption isotherms are presented. The many uses of water activity and sorption isotherms are also discussed. The best methods to measure water activity that exist nowadays are the electric hygrometers and the dew point hygrometer. The main disadvantage of these methods is that their cost is far too high for a significant part of the Brazilian food industry. A new method to measure water activity is proposed that should combine the speed required by the food industry and a low cost

Effect of pasteurization temperature on stability of an acidified sugarcane juice beverage

The shelf life of fresh sugarcane juice is quite limited due to the high rates of microbiological and enzymatic reactions which take place after extraction. In order to evaluate the impact of pasteurization temperature on quality and stability of sugarcane juice with passion fruit pulp, nine batches of sugarcane juice with 4g/100g passion fruit pulp were processed at 85, 90 and 95 °C for 30 s, in triplicate. The pasteurized beverage was aseptically packaged in polyethylene terephthalate (PET) bottles and stored at 7 °C in the dark. The beverage was characterized by physicochemical tests. Activities of polyphenol oxidase (PPO) and peroxidase (POD) were determined before and after processing. Coliforms and Salmonella tests were carried out to assure the beverage´s microbiological safety. Color parameters were measured in the processed juice throughout the storage period. Fifty panelists evaluated the beverage's appearance, aroma, flavor, and overall impression using seven-point hedonic scale tests. Sensory stability was estimated by considering score averages above four and percentages of acceptance above 60%. The pH, soluble solids and titratable acidity of end product ranged from 3.96 to 4.19, 19.7 to 20.1 ºBrix, and 0.163 to 0.175 g/100g citric acid, respectively. The three processing binomials were effective for PPO inactivation; however, complete POD inactivation was reached at 95 °C/30 s only. The estimated sensory shelf-lives for sugarcane juice with passion fruit pulp processed at 85, 90 and 95 °C/30 s were 30, 40 and 50 days, respectively. Thus, the increase of pasteurization temperature had a positive effect on product's stability

Natural antimicrobial ingredients incorporated in biodegradable films based on cassava starch

Biodegradable films based on cassava starch and with addition of natural antimicrobial ingredients were prepared using the casting technique. The tensile properties tensile strength (TS) [MPa] and percent elongation (E) at break [%] and the water vapor transmission (WVT) of the biodegradable films were evaluated and compared with the control (without antimicrobial ingredients). The evaluation of the Colony Forming Units per gram [CFU/g] of pan bread slices packed with the best biodegradable films, in terms of packaging performance, was also determined. The addition onto the matrix of only clove and cinnamon powders could reduce the films WVT when compared to the control, however TS and E were lower than the control and the effect of cinnamon was milder regarding this property. Since water activity of the pan bread slices packed with the biodegradable films increased considerably during the storage period, the antimicrobial effect could not be clearly determined. (C) 2010 Published by Elsevier Ltd.Brazilian Committee for Postgraduate Courses in Higher Education (CAPES)FAPESP (The State of Sao Paulo Research Foundation

Effect of Antimicrobial Edible Additives on Cassava Starch Biobased Films Characterization Written for presentation at the 2006 CIGR Section VI International Symposium on FUTURE OF FOOD ENGINEERING

Abstract. Antimicrobial films appear in response o

Cultivar affects the color change kinetics of sugarcane juice

Abstract This study evaluated the influence of different Brazilian cultivars (RB867515/C1, SP813250/C2, RB92579/C3 and CTC02/C4) on unprocessed sugarcane juice quality by physicochemical, microbiological and enzymatic analysis. Color parameters were determined during six days at 10 °C. The experimental design was completely randomized with four treatments (cultivars) and three replicates. Significant differences were observed (p ≤ 0.05) among the juice samples from different cultivars. The pH values ranged from 5.09 to 5.25, soluble solids content from 14.13 to 18.60 ºBrix and titratable acidity from 0.035 to 0.120% of citric acid. Counts of mesophiles, psychrotrophs and molds and yeasts varied between 4.8 and 6.2 logCFU mL-1, 3.2 and 4.6 logCFU mL-1 and 3.3 and 4.8 logCFU mL-1 , respectively. Polyphenol oxidase and peroxidase activities ranged from 8 to 15 U mL -1 and between 6 and 40 U mL-1, respectively. The initial (t0) lightness varied from 21 to 37 among cultivars, and final values, after six days of storage (t6), between 22 and 41. Principal components analysis showed that the juice of different cultivars is characterized by different parameters. Considering its lighter color and smaller color variation during storage, juice extracted from cultivar RB867515 presented the greatest potential for consumer acceptance

Cassava Starch Films Containing Quinoa Starch Nanocrystals: Physical and Surface Properties

Quinoa starch nanocrystals (QSNCs), obtained by acid hydrolysis, were used as a reinforcing filler in cassava starch films. The influence of QSNC concentrations (0, 2.5, 5.0, 7.5 and 10%, w/w) on the film’s physical and surface properties was investigated. QSNCs exhibited conical and parallelepiped shapes. An increase of the QSNC concentration, from 0 to 5%, improved the film’s tensile strength from 6.5 to 16.5 MPa, but at 7.5%, it decreased to 11.85 MPa. Adequate exfoliation of QSNCs in the starch matrix also decreased the water vapor permeability (~17%) up to a 5% concentration. At 5.0% and 7.5% concentrations, the films increased in roughness, water contact angle, and opacity, whereas the brightness decreased. Furthermore, at these concentrations, the film’s hydrophilic nature changed (water contact angle values of >65°). The SNC addition increased the film opacity without causing major changes in color. Other film properties, such as thickness, moisture content and solubility, were not affected by the QSNC concentration. The DSC (differential scanning calorimetry) results indicated that greater QSNC concentrations increased the second glass transition temperature (related to the biopolymer-rich phase) and the melting enthalpy. However, the film’s thermal stability was not altered by the QSNC addition. These findings contribute to overcoming the starch-based films’ limitations through the development of nanocomposite materials for future food packaging applications

Production and Evaluation of Yogurt Colored with Anthocyanin-Rich Pigment Prepared from Jabuticaba (<i>Myrciaria cauliflora</i> Mart.) Skin

Yogurt is known as a healthy food, but some synthetic additives that are commonly added to it can be one of the factors that restricts yogurt’s consumption. The aims of this study were to prepare and evaluate yogurts with the addition of spray-dried, anthocyanin-rich colorant extracted from jabuticaba (Myrciaria cauliflora Mart.) skin. The concentrated extract was spray-dried using maltodextrin (20 g/100 g w/w) as a carrier and added to yogurts in the concentrations of 0.5, 1.0, 1.5, and 2.0 g/100 g w/w. The yogurts were stored for up to 28 days under refrigeration and periodically evaluated. Except for the yogurts to which 1.5 g of extract was added, all samples had a slight pH reduction in the first 7 days of storage. Throughout the yogurts’ storage period, the anthocyanin and a* values were slightly reduced (p < 0.05), indicating some anthocyanin instability. The rheological behavior was typical for yogurts, but the casein gel network was probably disrupted by the jabuticaba extract incorporation, reducing the yogurt’s apparent viscosity. Panelists showed good acceptance for the attributes of taste, color, aroma, appearance, texture, and overall impression, indicating that this natural pigment has the potential to be a substitute synthetic color additive for the production of mixed berry yogurts, contributing to the reduction of waste