Evaluation of the use of rice protein hydrolysates as wall material in the microencapsulation of oil by "spray dryer"

Orientador: Louise Emy KurozawaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Nos últimos anos, o uso de proteínas vegetais em várias aplicações alimentares é uma tendência crescente na indústria de alimentos. Na microencapsulação por spray-drying, esses biopolímeros têm sido usados como um material de parede para uma variedade de compostos ativos. No entanto, devido à estrutura molecular complexa, as propriedades emulsificantes das proteínas não são totalmente exploradas. Sendo assim, a hidrólise enzimática é uma técnica adequada para melhorar as propriedades funcionais das proteínas, incluindo capacidade emulsificante e solubilidade, além de aumentar a capacidade antioxidante ao expor aminoácidos antioxidantes presentes na cadeia proteica. Diante disso, o presente trabalho teve como objetivo avaliar hidrolisados proteicos de proteínas de arroz como material de parede junto com a maltodextrina e avaliar o potencial antioxidante desses hidrolisados em micropartículas de óleo de linhaça secas por spray-drying. Foram utilizadas duas enzimas com ação catalíticas distintas, Alcalase e Flavourzyme, na hidrólise limitada (grau de hidrólise (GH) 1, 2, 4, 8 e 10%) de proteínas isoladas de arroz. A enzima Alcalase produziu peptídeos menores e com maior capacidade antioxidante, consequentemente apresentaram emulsões mais instáveis no maior grau de hidrólise, isso devido à forte tendência a agregação entre os peptídeos gerados e baixa capacidade emulsificante. Em contraste, as emulsões estabilizadas com hidrolisados da Flavourzyme exibiram gotículas de óleo menores e maior estabilidade durante a secagem (GH 10%) comparadas com a proteína intacta e os hidrolisados da Alcalase. Refletindo a forte tendência antioxidante observadas nos testes de DPPH e FRAP, os hidrolisados da Alcalase exibiram um potencial maior do que o a proteína isolada e hidrolisados da Flavouzyme para reduzir a oxidação lipídica das micropartículas de óleo de linhaça durante o armazenamento, como demonstrado pelo teste Rancimat e índice de peróxido. Além disso, a análise de DSC mostrou que as micropartículas obtidas com hidrolisados proteicos apresentaram valores de Tg menores que aqueles contendo proteínas não hidrolisadas. A utilização de enzimas com atividade em sítios ativos distintos resulta em peptídeos com tamanhos, funcionalidade e capacidade antioxidante diferentes que influenciam diretamente no processo e na estabilidade das micropartículasAbstract: In recent years, the use of plant protein in various food applications is an increasing trend in the food industry. In the process of microencapsulation by spray-drying these biopolymers have been used as a wall forming material for a variety of active compounds. However, due to the complex molecular structure, the emulsifying properties of the proteins are not fully exploited. Thus, enzymatic hydrolysis is a suitable technique for improving the functional properties of proteins, including emulsifying ability and solubility, and increasing the antioxidant capacity by exposing antioxidant peptides present in the protein chain. Therefore, the present work aimed to evaluate the protein hydrolysates of rice proteins as wall material of dried linseed oil microcapsules by spray-drying. The use of two distinct catalytic enzymes, Alcalase and Flavourzyme, in the limited hydrolysis (degree of hydrolysis (GH) 1, 2, 4, 8 and 10%) of proteins isolated from rice, proved that the different peptides obtained influenced the of stable emulsions, in protecting the microcapsules against oxidation and structure. The enzyme Alcalase produced smaller peptides with higher antioxidant capacity, consequently they presented more unstable emulsions with the increase of the degree of hydrolysis, due to the strong tendency of aggregation between the peptides generated. In contrast, emulsions stabilized with Flavourzyme hydrolysates exhibited lower oil droplets and greater stability during drying (10% GH) compared to intact protein and Alcalase hydrolysates. Reflecting the strong antioxidant tendency observed in the DPPH and FRAP tests, Alcalase hydrolysates exhibited a greater potential than the isolated protein and Flavouzyme hydrolysate to reduce lipid oxidation of linseed oil microcapsules during storage as demonstrated by the test Rancimat and peroxide index. In addition, DSC analysis showed that microparticles encapsulated by protein hydrolysates had lower Tg values than those containing non-hydrolyzed proteins. The use of enzymes with activity at distinct active sites results in peptides with different sizes, functionality and antioxidant capacity that will directly influence the process and stability of the microcapsulesMestradoEngenharia de AlimentosMestre em Engenharia de Alimentos405535/2018-0CNP

Improvement of the functional and antioxidant properties of rice protein by enzymatic hydrolysis for the microencapsulation of linseed oil

In this study, the potential use of rice protein hydrolysates as emulsifying and encapsulating agents in the microencapsulation of linseed oil by spray drying was evaluated. The proteases Alcalase and Flavourzyme were used to obtain protein hydrolysates with various degrees of hydrolysis from rice protein isolate. Linseed oil-in-water emulsions stabilized by maltodextrin and protein hydrolysates obtained by Alcalase or Flavourzyme were characterized by oil droplet size, ζ-potential, rheological behavior, emulsion stability, and emulsion capacity. The emulsions were spray dried and evaluated according to their encapsulation efficiency and lipid oxidation stability. The results showed that the emulsions stabilized by Flavourzyme protein hydrolysate presented smaller oil droplets and were more stable than Alcalase protein hydrolysate and rice protein isolate, resulting in high encapsulation efficiency (89.5%) for higher degree of hydrolysis. In contrast, microparticles containing Alcalase protein hydrolysate reduced the lipid oxidation of linseed oil during storage, due to higher antioxidant capacity of the protein hydrolysate267CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP405535/2018-00012009/54137-1; 2011/504230-

Partitioning and extraction protease from Aspergillus tamarii URM4634 using PEG-citrate aqueous two-phase systems

PEG-citrate Aqueous Two-Phase Systems (ATPS) were used to recover and partially purify protease from Aspergillus tamarii URM4634 produced by Solid State Fermentation. Experiments were performed according to a 24-full factorial design using PEG molar mass (MPEG), PEG concentration (CPEG), citrate concentration (CCIT) and pH as independent variables; and purification factor (PF), partition coefficient (K) and activity yield (Y) as responses. Protease showed high activity in the PEG-rich phase, also MPEG and CCIT were shown to exert positive effects on all responses. The highest purification factor (3.95) was obtained using MPEG=8000 g/mol, 24% (w/w) CPEG, 20% (w/w) CCIT at pH 8.0. Consequently, the selected ATPS proved to be efficient and can be used as a first step for pre-purification of protease from solid state fermented of A. tamarii URM4634

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved