Mechanical properties of castor beans subject to different drying temperatures aiming to disrupt the bean coat

Abstract

ABSTRACT:In castor oil extraction process, the bean coat is abrasive to the equipment and releases substances that modify the oil color, reducing its quality. A potential solution would be to run the extraction by compressing only the endosperm. Due to lack of information, the objective of this study was to evaluate the influence of forced air drying at 40, 60, 80 and 100 ºC and farmyard drying, in the mechanical properties of the beans, aiming to break the bean coat. Castor beans were subjected to compression tests, in two perpendicular directions, at a strain rate of 0.6 mm.s-1. Average values of force, deformation energy, strain, all at rupture, and stiffness were used to evaluate the effects of dehydration. It was observed that the heat treatments did not alter the mechanical properties of castor beans, the strain and stiffness values discriminate the differences between the directions and had the lowest coefficients of variation. It was concluded that forced air drying, more costly than farmyard drying, does not bring benefits to the decortication. However, regardless the heat treatment used, the mechanical stress lengthwise is the most suitable to promote decortication. KEYS-WORDS:conditioning, threshing, decortication, compression. PROPRIEDADES MECÂNICAS DOS GRÃOS DE MAMONA SUBMETIDOS A DIFERENTES TEMPERATURAS DE SECAGEM A VISANDO A RUPTURA DO TEGUMENTO RESUMO:No processo de extração do óleo de mamona, o tegumento libera substâncias que modificam a coloração do óleo, reduzindo a qualidade, e causa abrasão nos equipamentos. Potencialmente, uma solução para esse problema seria executar a extração prensando somente o endosperma. Devido à carência de informações, o objetivo deste trabalho foi avaliar a influência da secagem com ar forçado a 40; 60; 80 e 100 ºC e secagem em terreiro, nas propriedades mecânicas dos grãos, visando ruptura do tegumento. Grãos de mamona foram submetidos a ensaios de compressão, em duas direções perpendiculares, com taxa de deformação de 0,6 mm.s -1 . Valores médios da força, energia de deformação, deformação específica, todos na ruptura, e rigidez foram utilizados para a avaliação dos efeitos da secagem. Observou-se que, nas condições consideradas, os tratamentos térmicos não alteraram as propriedades mecânicas dos grãos de mamona e que os valores de deformação específica e rigidez discriminaram as diferenças entre as direções e apresentaram os menores coeficientes de variação. Concluiu-se que a secagem com ar forçado, mais oneroso que a secagem no terreiro, não traz benefícios à decorticação. No entanto, independentemente do tratamento térmico, a solicitação mecânica do grão na direção longitudinal é a mais indicada para promover a decorticação.

Physical characteristics of baru tree fruit aimed at kernel extraction

“…For all tests, the specimens were carefully accommodated between plates, applying a minimum preload just sufficient to hold the specimen vertically along its width. Force-deformation curves were obtained from tests, allowing the determination of mechanical parameters such as maximum force (N), and their corresponding deformation (mm), specific deformation (% or decimal), and deformation energy (J), similar to other works for mechanical characterization of biological materials (BASTOS; FERRAZ, 2014;GHARIBZAHEDI et al, 2012aGHARIBZAHEDI et al, , 2012bOGUNSINA;BAMGBOYE, 2013). Using the curves, the maximum force and its deformation (δ) were identified, allowing the calculation of the average specific strain (ε), expressed by the ratio between deformation values (δ) and initial width (L 0 ), both measured in mm.…”

Sustainable castor oil-based semi-aromatic copolyesters with high strength and low hydrolysis

“…The success of the PT(T x A y )-C n copolymer synthesis was thus confirmed. 37,64,79 All characteristic data are presented in Table 2.…”

“…43 Its unique structure with three reactive sites of the double bond, ester bond, and hydroxyl group allows various possibilities for copolymerization [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] and diverse mechanical properties. [63][64][65][66][67] The dangling chains on the segments also influence the physical behaviors and enhance the hydrophobicity. These chains can reduce the glass transition temperatures of the polyesters.…”

Polymers and Composites Derived from Castor Oil as Sustainable Materials and Degradable Biomaterials: Current Status and Emerging Trends

“…Several researchers have the availability of three reactive sites (double bond, ester linkage, and hydroxyl group) in RA by for their studies. The presence of the carboxylic acid group in CO helps in esterification − and amidation, , whereas the double bond affords hydrogenation − and epoxidation. − The presence of the hydroxyl group in CO helps in acetylation , and alkoxylation, and/or maybe removed by dehydration. − Consequently, this unique functionality helps in preparing a wide variety of polymers such as polyethers, polyesters, polyamides, and interpenetrating polymer networks (IPNs), which exhibit distinct mechanical and physical properties. − Moreover, the dangling chain present in RA imposes hydrophobicity and influences the physical and mechanical properties of the polymers . Most of these CO polymers accelerate the synthesis of polyurethane (PU), poly­(2-hydroxyethyl methacrylate), poly­(lactic acid) (PLA), and sometimes blended with commercially available poly­(methyl methacrylate) (PMMA), polystyrene, and poly­(vinyl alcohol).…”