Conventional and Unconventional Crystallization Mechanisms

Understanding the crystallization behavior of fats and oils is essential to ensure certain desirable characteristics in a given industrial application. In recent years, some advances in the structuring of lipid phases have enabled a direct influence on the food properties. The structuring mechanisms of lipid bases can be classified as either conventional or unconventional. Conventional crystallization mechanisms consist of nucleation, growth, and maturation of the crystals, thus resulting in a crystalline lattice. Co-crystallization or seeding agents and emerging technologies such as ultrasound can be used to aid in crystallization and improve the physical properties of fats and oils. Unconventional mechanisms bring organogel technology as a trend, which consists in the use of self-assembly agents to entrap the liquid oil, resulting in a structured gel network. In this chapter, the formation process of crystalline networks and gel networks will be presented in stages, highlighting the main differences related to the mechanisms of formation and stabilization of both types of networks

Sucrose behenate as a crystallization enhancer for soft fats

AbstractThe addition of sucrose behenate for the modification of the physical properties of soft fats, such as soybean oil-based interesterified fat, refined palm oil, and palm mid fraction was studied. The addition of sucrose behenate was verified to affect the crystalline network of fats, changing the hardness and solids profile. The isothermal crystallization behaviors of the fat blends with 1% sucrose behenate were analyzed at 20 and 25°C. Temperature had a greater effect on the speed of crystallization (k) than the presence of the emulsifier. Sucrose behenate did, however, influence the crystallization mechanism, with changes observed in the Avrami exponent (n). These changes were also observed in the microstructure of the fats. Changes in the polymorphic behavior were observed with the addition of sucrose behenate, such as a possible delay in the α→β transition for interesterified fat, and the initial formation of the β polymorph in palm oil

Evaluation of emulsifiers addition on the crystallization properties of industrial fats

Orientador: Lireny Aparecida Guaraldo GonçalvesTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: A cristalização de gorduras é um fator crítico associado à estruturação e propriedades de grande parte dos alimentos. No Brasil, as questões controversas acerca do papel dos ácidos graxos trans na alimentação ocasionaram modificações progressivas na legislação e no uso industrial de gorduras, levando à substituição das gorduras parcialmente hidrogenadas por gorduras interesterificadas, fracionadas ou blends. Considerando que este processo de substituição foi ampliando, os problemas de comportamento de cristalização devido à não adequação das novas frações gordurosas são inúmeros e agravados, principalmente, pelas diferenças climáticas regionais e condições de transporte e estocagem. Logo, a adequação da cinética de cristalização destas bases gordurosas é de extrema importância para que o uso das mesmas possa ser ajustado às limitações dos processos industriais e para melhorar o controle de etapas de processamento que envolva recristalização da fração gordurosa, garantindo a qualidade do produto final. Caso contrário, os tempos de processamento e equipamentos já padronizados precisam ser alterados segundo as características da gordura utilizada. Emulsificantes são aditivos funcionais de extrema importância na indústria de alimentos, que podem ser utilizados para controlar ou modificar as propriedades de cristalização da fase gordurosa. O estudo dos efeitos de emulsificantes em sistemas gordurosos é de grande interesse para o melhoramento de novas bases gordurosas com finalidades específicas, uma vez que propriedades apropriadas de cristalização são de difícil obtenção quando da ausência de ácidos graxos trans. O papel destes compostos como modificadores de cristalização em gorduras naturais e comerciais é pouco explorado, constituindo-se em um assunto inovador sob o ponto de vista da indústria de alimentos. Neste contexto, o objetivo deste trabalho foi avaliar o efeito da incorporação de ésteres de sorbitana e sacarose sobre as propriedades de cristalização da gordura interesterificada base soja, do óleo de palma e da fração mediana de palma (soft PMF). Estas gorduras industriais apresentam algumas limitações quanto a sua aplicação, especialmente relacionadas com determinadas propriedades, tais como: consistência e plasticidade dos produtos durante as etapas de produção e estocagem; propriedades sensoriais, como sensação de fusão na boca; estabilidade física, com respeito à formação ou sedimentação de cristais e exsudação de óleo; e aparência visual, a exemplo do brilho em chocolates e coberturas. Portanto, o presente trabalho mostra grande relevância para o setor produtivo de óleos e gordurasAbstract: Fat crystallization is a critical factor associated with either structuring or properties of most foods. In Brazil, controversial issues about the role that trans fatty acid plays on food gave rise to progressive changes in the legislation as well as in the industrial use of fat, which leads to partial substitution of hydrogenated fat by interesterified, fractionated or blended fat. Considering that this substitution process was expanded, problems regarding crystallization behavior are countless and even aggravated because the new fat fractions are not adequate, mainly for regional climatic differences, transportation and storage conditions. Therefore, the crystallization kinetic inadequacy of such fatty bases is extremely important, so that their use can fit the industrial process limitation purposes and improve the control on processing stages that involve recrystallization of fat fractions, ensuring the quality of the final product. Otherwise, time processing and equipment already brought into line need to be changed according to the characteristics of the fat used. Emulsifiers are extremely important functional additives in food industry and can be used to either control or modify the crystallization properties in the fatty stage. The study of emulsifiers effects on fatty systems is of great interest to improve new fatty bases with specific purposes, since appropriate crystallization properties are difficult to obtain when trans fatty acid lacks. The role of these compounds as crystallization modifiers in natural and commercial fat is not much investigated, thus constituting an original subject under the food industry point of view. In this context, the aim of this study was to evaluate the effect of addition of sorbitan and sucrose esters on the crystallization properties of interesterified fat based soy, palm oil and palm median fraction (soft PMF). These industrial fats present some limitations regarding their application, especially related to certain properties, such as: product consistency and plasticity during the stages of production and storage; sensory properties like melting sensation in the mouth; physical stability with respect to crystal formation or sedimentation and oil exudation; and visual appearance, like the glint in chocolates and coatings. Therefore, this work shows highly relevant to the productive sector of oils and fatsDoutoradoTecnologia de AlimentosDoutora em Tecnologia de Alimento

Nutritional, functional and biological properties of insect proteins: processes for obtaining, consumption and future challenges

Consuming insects as an alternative protein source is considered a future trend and a viable strategy that could potentially contribute to global food security. Insects are a non-conventional source of protein, either for human consumption directly or indirectly as a component in recomposed foods or added to feedstock mixtures. Moreover, these proteins have demonstrated a broad range of applications as peptides with antihypertensive, antimicrobial and antioxidant properties. However, aspects such as food safety and processing of these proteins need further studies for their elucidation and optimization. In this review, aspects of nutritional value and risks of insect consumption are reported. Additionally, conventional processing techniques and recent advances in insect protein extraction and production are presented. The application of bioactive peptides obtained from insect protein hydrolysates is reported, focusing on their potential antihypertensive, antimicrobial and antioxidant properties. Insect proteins have great advantages in terms of nutritional value, total protein level and amino acid profile. However, some safety concerns must be taken into consideration in large-scale production. The conventional processing of insects proteins is very particular, depending on several aspects such as species, larval stage, and cultivation, among others. Nonetheless, recent advances in insect protein production via enzymatic hydrolysis and heterologous expression have shown a promising technology for the study and exploitation of their bioactive properties, such as the antimicrobial, antioxidant and antihypertensive (inhibition of ACE) activity of insect peptides.76828

Structural characteristics of crystals formed in palm oil using sorbitan tristearate and sucrose stearate

The formation and stabilization of fat crystals in palm oil (PO) by the templating effects of sorbitan tristearate (STS) and sucrose stearate (S-370) were examined. We observed that the crystallization mechanism occurred via heterogeneous nucleation, which was induced by co-crystallization or seeding, after the addition of STS or S-370, respectively. Overall, both emulsifiers, STS and S-370, caused an increase in the hardness of PO, which was related to changes in the microstructure. In addition, the intensity of this effect was shown to be dependent on the emulsifiers concentration. In differential scanning calorimetry analysis, S-370 proved to be associated predominantly to the crystallization of high-melting triacylglycerols (TAGs), while STS showed to actuate the crystallization of high and low-melting TAGs. Moreover, the addition of STS improved the polymorphic stability of the PO, while the use of S-370 resulted in a soft texture at lower temperatures21161863

Structural characteristics of crystals formed in palm oil using sorbitan tristearate and sucrose stearate

The formation and stabilization of fat crystals in palm oil (PO) by the templating effects of sorbitan tristearate (STS) and sucrose stearate (S-370) were examined. We observed that the crystallization mechanism occurred via heterogeneous nucleation, which was induced by co-crystallization or seeding, after the addition of STS or S-370, respectively. Overall, both emulsifiers, STS and S-370, caused an increase in the hardness of PO, which was related to changes in the microstructure. In addition, the intensity of this effect was shown to be dependent on the emulsifiers concentration. In differential scanning calorimetry analysis, S-370 proved to be associated predominantly to the crystallization of high-melting triacylglycerols (TAGs), while STS showed to actuate the crystallization of high and low-melting TAGs. Moreover, the addition of STS improved the polymorphic stability of the PO, while the use of S-370 resulted in a soft texture at lower temperatures