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Abstract(s)
A procura de snacks convenientes e nutritivos aliada ao ritmo acelerado a que vivem os consumidores despoletou o crescente consumo de barras com proteína nos últimos anos. Respondendo a esta tendência, o objetivo deste trabalho incidiu no desenvolvimento de uma barra de cereais rica em proteína. Foram preparadas barras de cereais através da mistura de ingredientes secos envolvidos pelo ligante (resultante da cozedura a uma temperatura superior a 100ºC de ingredientes ligantes). Foram testadas 9 proteínas em pó de origem vegetal e animal (leite, soro de leite, trigo, ervilha e alga), que foram incorporadas nos ingredientes ligantes. Este trabalho permitiu concluir sobre a viabilidade tecnológica das proteínas no ligante, identificando-se dois fatores chave: a temperatura (efeito do seu aumento no desenvolvimento de um escurecimento ou consistência indesejáveis ou pela agregação/gelificação das proteínas) e a solubilidade (prevenção de partículas em suspensão). Adicionalmente, também se observou o seu impacto organolético nas barras (cor, sabor e textura). No geral, concluiu-se que as proteínas vegetais apresentaram melhor desempenho na cozedura do ligante, porém foram mais desafiantes sensorialmente (má palatibilidade), à exceção da proteína de trigo solúvel, que permitiu obter uma formulação mais promissora para ser testada a nível industrial. Neste protótipo, consideraram-se bastante próximos os resultados obtidos em amostras no teor de proteína (por 100 g) pelos cálculos nutricionais (18,19 g), pela análise NIR (18,67 ± 0,47 g) e no laboratório acreditado externo (18,02 g). Os valores obtidos no teor de humidade pelo método NIR (7,92 ± 0,12 %) e gravimétrico (7,92 ± 0,18 %), bem como, a atividade da atividade da água (0,445 ± 0,004) encontraram-se consonantes com os referenciados para produtos de humidade intermédia. À escala industrial obtiveram-se resultados insatisfatórios no desempenho do ligante: a sua consistência densa não permitiu a mistura com os ingredientes secos no primeiro lote; a aglomeração da proteína no segundo lote inviabilizou a formação de barras. No entanto, ressalva-se o facto de dois lotes não serem suficientes para otimizar todos os parâmetros de processo à escala industrial quando se trata de um desenvolvimento pioneiro. Neste âmbito, diferentes alterações podem ser consideradas, por exemplo, testar diferentes temperaturas de cozedura; adquirir um agitador para o tanque de cozedura mais eficaz; incluir a etapa de reconstituição de proteína em água antes da etapa de cozedura ou pela alteração da sequência de adição de ingredientes no ligante antes da etapa de cozedura. Em termos de reformulação da composição do ligante, a validação e teste à escala laboratorial de proteínas em pó e extrudidos de proteína alternativos; a incorporação de misturas de proteínas; ou o revestimento parcial ou total de coberturas proteicas são também possíveis soluções para trabalhos experimentais futuros.
The growing demand for convenient and nutritious snacks combined with the accelerated pace at which consumers live has triggered the increasing consumption of protein bars in the recent years. Answering to this trend, the objective of this work focused on the development of a protein-rich cereal bar. Cereal bars were prepared by mixing dry ingredients and binder (resulting from cooking at a temperature above 100ºC of binding ingredients). 9 protein powder of plant and animal origin (milk, whey, wheat, pea and algae) were tested and included in the binding ingredients. This work allowed to conclude on the technological viability of proteins added to the binder, identifying two key factors: temperature (effect of its increase on the development of undesirable darkening or consistency or by the aggregation/gelling of proteins) and solubility (prevention of particle suspension). In addition, its organoleptic impact on bars (colour, taste and texture) was also observed. Overall, it was concluded that vegetable proteins presented better performance in binder cooking, but were more sensory challenging (poor palatability), with the exception of soluble wheat protein, which made it possible to obtain a suitable formulation for industrial testing. In this prototype, the results obtained for samples in terms of the protein content (per 100g) were considered to be very close by theoritical calculations (18,19g), by NIR analysis (18,67 ± 0,47g) and by the accredited external laboratory (18,02g). The values obtained for moisture content by the NIR (7,92 ± 0,12 %) and gravimetric (7,92 ± 0,18 %) methods, as well as water activity (0,445 ± 0,004) were aligned with those referenced for intermediate moisture products. On industrial scale, unsatisfactory results were obtained in the binder's performance: its thick consistency didn’t allow mixing with the dried ingredients in the first batch; the protein agglomeration in the second batch made it inoperable to form bars. However, it should be noted that two batches are not sufficient to optimize all process parameters on an industrial scale when it comes to pioneering development. In this regard, different changes may be considered, for example, testing different cooking temperatures; purchase a stirrer more effective for the cooking tank; include the step of reconstituting protein in water prior to the cooking or by changing the ingredient addition sequence in the binder prior to the cooking step. In terms of reformulation of the binder composition, laboratory validation and testing of alternative protein powders and extrudates; the incorporation of protein mixtures; or partial or full coating of protein coatings are also possible solutions for future experimental work.
The growing demand for convenient and nutritious snacks combined with the accelerated pace at which consumers live has triggered the increasing consumption of protein bars in the recent years. Answering to this trend, the objective of this work focused on the development of a protein-rich cereal bar. Cereal bars were prepared by mixing dry ingredients and binder (resulting from cooking at a temperature above 100ºC of binding ingredients). 9 protein powder of plant and animal origin (milk, whey, wheat, pea and algae) were tested and included in the binding ingredients. This work allowed to conclude on the technological viability of proteins added to the binder, identifying two key factors: temperature (effect of its increase on the development of undesirable darkening or consistency or by the aggregation/gelling of proteins) and solubility (prevention of particle suspension). In addition, its organoleptic impact on bars (colour, taste and texture) was also observed. Overall, it was concluded that vegetable proteins presented better performance in binder cooking, but were more sensory challenging (poor palatability), with the exception of soluble wheat protein, which made it possible to obtain a suitable formulation for industrial testing. In this prototype, the results obtained for samples in terms of the protein content (per 100g) were considered to be very close by theoritical calculations (18,19g), by NIR analysis (18,67 ± 0,47g) and by the accredited external laboratory (18,02g). The values obtained for moisture content by the NIR (7,92 ± 0,12 %) and gravimetric (7,92 ± 0,18 %) methods, as well as water activity (0,445 ± 0,004) were aligned with those referenced for intermediate moisture products. On industrial scale, unsatisfactory results were obtained in the binder's performance: its thick consistency didn’t allow mixing with the dried ingredients in the first batch; the protein agglomeration in the second batch made it inoperable to form bars. However, it should be noted that two batches are not sufficient to optimize all process parameters on an industrial scale when it comes to pioneering development. In this regard, different changes may be considered, for example, testing different cooking temperatures; purchase a stirrer more effective for the cooking tank; include the step of reconstituting protein in water prior to the cooking or by changing the ingredient addition sequence in the binder prior to the cooking step. In terms of reformulation of the binder composition, laboratory validation and testing of alternative protein powders and extrudates; the incorporation of protein mixtures; or partial or full coating of protein coatings are also possible solutions for future experimental work.
Description
Keywords
Barra de cereais rica em proteína Proteínas do leite Proteínas vegetais Viabilidade tecnológica Impacto sensorial Protein-rich cereal bars Milk proteins Plant-based proteins Technological viability Sensory impact