Caracterização química de farinha de cenoura e cenoura in natura com casca / Chemical characterization of carrot flour in natura with nuts

A cenoura é uma hortaliça bastante utilizada pela indústria alimentícia. Possui carotenoide, o qual desempenha um importante papel como potente antioxidante. Afim de se evitar desperdício e garantir maior vida de prateleira, este trabalho teve como objetivo analisar quimicamente farinha de cenoura e cenoura in natura, ambas com casca. As cenouras foram trituradas e congeladas a -18 °C. Parte da amostra foi secada em câmara climática a 60 °C por 45h, em seguida, a cenoura in natura e a farinha de cenoura foram submetidas a análises químicas e físico-químicas. A análise do teor de água mostrou que a farinha de cenoura está de acordo com os padrões estabelecidos pela Legislação Brasileira. A cenoura após secagem, apresentou concentração quanto aos níveis de proteínas, fibras, carotenoides e polifenóis totais em relação a cenoura in natura.

Ultrasound- and microwave-assisted convective drying of carrots - Process kinetics and product's quality analysis.

The aim of these studies was to investigate the influence of airborne ultrasound-assisted convective drying and microwave-assisted convective drying, as well as their combination, on process kinetics, total color change, water activity, content of carotenoids, polyphenols and antioxidant activity of carrots (Daucus carota L.). The global model of drying kinetics based on coupled ordinary differential equations was used to describe the moisture and material temperature profiles during drying. Application of ultrasound and microwave in convective drying reduced drying time in the range of 9-81%, but the shortest drying time was observed for simultaneous action of convection, ultrasound and microwave. The results of qualitative analysis showed a product improvement due to ultrasound as compared to convective drying and microwave-convective drying. The proposed mathematical model of drying kinetics successfully simulated real drying processes. The proposed mathematical model of drying kinetics successfully simulated real hybrid drying processes.

Molecular characterization of spoilage bacteria as a means to observe the microbiological quality of carrot.

This study characterized the bacteria causing decay of carrots during storage and marketing. Spoilage strains were identified by 16S-amplified rDNA restriction analysis and intergenic transcribed spacer-PCR-restriction fragment length polymorphism (ITS-PCR-RFLP). Genotypic fingerprinting by RFLP-pulsed-field gel electrophoresis was used to assess the genetic diversity of the isolates. A total of 252 Pseudomonas isolates from carrots were identified and classified into eight separate groups. Most strains belonged to group A (Pseudomonas fluorescens, Pseudomonas marginalis, and Pseudomonas veronii) and group B (Pseudomonas putida). The strains identified as Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, Dickeya chrysanthemi, and Erwinia rhapontici were distinguished by ITS-PCR-RFLP. All isolates belonging to the genera Pectobacterium and Erwinia were responsible for carrot spoilage. This work has led to the development of new strategies for the identification and genotyping of vegetable-spoiling strains of Pseudomonas, Pectobacterium, and Erwinia. This is also the first report describing the occurrence of carrot-spoiling E. rhapontici. Early recognition of spoilage bacteria in vegetables is important for the implementation of effective handling strategies. Pectolytic bacteria may cause considerable financial losses because they account for a large proportion of bacterial rot of fruits and vegetables during storage, transit, and marketing.

Combination treatment of alkaline electrolyzed water and citric acid with mild heat to ensure microbial safety, shelf-life and sensory quality of shredded carrots.

The objective of this study was to determine the synergistic effect of alkaline electrolyzed water and citric acid with mild heat against background and pathogenic microorganisms on carrots. Shredded carrots were inoculated with approximately 6-7 log CFU/g of Escherichia coli O157:H7 (932, and 933) and Listeria monocytogenes (ATCC 19116, and 19111) and then dip treated with alkaline electrolyzed water (AlEW), acidic electrolyzed water (AcEW), 100 ppm sodium hypochlorite (NaOCl), deionized water (DaIW), or 1% citric acid (CA) alone or with combinations of AlEW and 1% CA (AlEW + CA). The populations of spoilage bacteria on the carrots were investigated after various exposure times (1, 3, and 5 min) and treatment at different dipping temperatures (1, 20, 40, and 50 °C) and then optimal condition (3 min at 50 °C) was applied against foodborne pathogens on the carrots. When compared to the untreated control, treatment AcEW most effectively reduced the numbers of total bacteria, yeast and fungi, followed by AlEW and 100 ppm NaOCl. Exposure to all treatments for 3 min significantly reduced the numbers of total bacteria, yeast and fungi on the carrots. As the dipping temperature increased from 1 °C to 50 °C, the reductions of total bacteria, yeast and fungi increased significantly from 0.22 to 2.67 log CFU/g during the wash treatment (p ≤ 0.05). The combined 1% citric acid and AlEW treatment at 50 °C showed a reduction of the total bacterial count and the yeast and fungi of around 3.7 log CFU/g, as well as effective reduction of L. monocytogenes (3.97 log CFU/g), and E. Coli O157:H7 (4 log CFU/g). Combinations of alkaline electrolyzed water and citric acid better maintained the sensory and microbial quality of the fresh-cut carrots and enhanced the overall shelf-life of the produce.

Evaluation of the instrumental quality of pressure-assisted thermally processed carrots.

This study was conducted to compare the effectiveness of pressure-assisted thermal processing (PATP) in preserving the texture, color, and carotene content of carrot cylinders in the pressure range of 500 to 700 MPa and the temperature range of 95 to 121 degrees C. The effectiveness of PATP was compared with that of conventional thermal processing (TP) by matching carrot preprocess temperature history. Results indicated that under comparable process temperatures (up to 105 degrees C), PATP retained the carrot quality attributes such as color and carotene content better than TP. However, process and preprocess thermal history at 121 degrees C greatly influenced carrot textural change and pressure protective effects were less pronounced. This study demonstrated that PATP has the potential to produce low-acid foods with a relatively better quality than TP.

Sanitation procedure affects biochemical and nutritional changes of shredded carrots.

Fresh-cut vegetables are considered convenient but with less nutritional quality compared to raw natural produce. Carrots are highly appreciated because of their carotene and antioxidant nutrients, but processing requires an appropriate sanitation procedure that ensures microbiological safety to consumers. The effect of the sanitation processing on the nutritional composition of shredded carrots was studied. Treatments tested were tap water, 200 ppm sodium hypochlorite (Cl), 40 ppm peroxyacetic acid (PA), and 100, 250, and 500 ppm acidified sodium chlorite (ASC). Measured parameters were oxygen radical absorbing capacity (ORAC), total phenolics and carotenoids, sugars, and phenylalanine ammonia lyase (PAL) and peroxidase (POD) activity. Shredded carrots sanitized with ASC retained higher levels of sugars, carotene, and antioxidant capacity. ASC also delayed the PAL and POD activity. These results show the importance of evaluating nutritional parameters during processing stages, since minimal processing does not necessarily imply loss of nutritional value. Furthermore, the availability of fresh-cut produce may increase the intake of nutrients, with a positive effect on health.

Combined effects of coating, modified atmosphere packaging, and gamma irradiation on quality maintenance of ready-to-use carrots (Daucus carota).

The objective of this study was to evaluate the effect of an edible coating combined with modified atmosphere (MA; 60% O2, 30% CO2, and 10% N2) packaging and gamma irradiation on the microbiological stability and physicochemical quality of minimally processed carrots. A coating based on calcium caseinate and whey protein isolates was used. Coated and uncoated peeled minicarrots were packed under the MA or air (78.1% N2, 20.9% O2, and 0.036% CO2), irradiated at 0.5 or 1 kGy, and stored at 4 +/- 1 degrees C for 21 days. Samples were evaluated periodically for aerobic plates counts (APCs) and physicochemical properties (firmness, white discoloration, and whiteness index). Gamma irradiation did not significantly affect the physicochemical properties of the carrots (P > 0.05). Microbiological analysis revealed that for uncoated carrots irradiation at 0.5 and 1 kGy under air and MA reduced the APCs by 3.5 and 4 log CFU/g and by 4 and 4.5 log CFU/g, respectively. For coated carrots, irradiation at 0.5 and 1 kGy under air and MA reduced the APCs by 4 and 4.5 log CFU/g and by 3 and 4.25 log CFU/g, respectively. The coating was able to protect carrots against dehydration during storage under air. Coating and irradiation at 1 kGy were also able to protect carrot firmness during storage under air. MA packaging retarded whitening of uncoated carrots but had a detrimental effect on firmness. The edible coating used in this study did not significantly inhibit (P > 0.05) microbial growth on carrots.