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Análise comparativa da vida útil da borra de café em diferentes embalagens
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A borra de café, é um dos subprodutos produzidos pela indústria do café, que pela sua composição em diversos compostos bioativos, revela-se um potencial substrato para o desenvolvimento de produtos de valor acrescentado. No entanto, os desafios logísticos associados à sua recolha, assim como a rápida degradação microbiológica, representam uma barreira à conservação e subsequente reutilização. Neste contexto, o presente trabalho teve como objetivo realizar uma análise comparativa da estabilidade e vida útil da borra de café armazenada em cinco embalagens diferentes ao longo de 15 dias. As embalagens selecionadas para o estudo apresentam um conjunto de propriedades promissoras à redução da proliferação de microrganismos e durabilidade da borra, e foram as seguintes: amido de milho (E1), kraft (E2), kraft com 50g de sílica gel (E3), kraft com 25g de cloreto de cálcio (E4) e polietileno a vácuo (E5). Para cumprir com o objetivo proposto, foram colocadas 100g de borra de café, proveniente da recolha após 24h de atividade de produção de uma cafetaria, em cada embalagem, e monitorizaram-se alguns parâmetros físico-químicos (cor, pH, humidade, atividade da água) e microbiológicos (microrganismos a 30 ºC e bolores e leveduras) da borra armazenada aos dias 0, 2, 5, 7 e 15. Paralelamente, foi realizada uma análise ao ciclo de vida, com base na compilação de dados disponíveis na literatura, e com o propósito de avaliar o impacto ambiental associado a cada material das embalagens em estudo. Os resultados deste projeto, evidenciaram que a E5, foi estatisticamente mais eficaz na preservação dos parâmetros da cor e do pH, principalmente devido à ausência de oxigénio. A E1 e a E4, permitiram uma maior redução da humidade e atividade da água, justificada pela elevada taxa de transferência de vapor de água e capacidade dessecante do cloreto de cálcio, respetivamente. Do ponto de vista microbiológico, comprovou-se que a borra tem uma elevada carga inicial de microrganismos a 30 ºC, e no caso dos bolores e leveduras, a E5 foi a mais eficaz no controlo da proliferação dos mesmos ao longo do tempo. A análise do ciclo de vida, permitiu percecionar que a E5 apresenta uma menor pegada ambiental para as categorias de impacto consideradas, sobretudo pelo facto da produção do papel kraft e do amido de milho apresentarem uma elevada variabilidade e maior potencial de poluição em certas etapas. Em conclusão, este estudo demonstrou uma clara correlação entre o tipo de embalagem utilizada e a estabilidade da borra de café ao longo do tempo, sendo que a E5 parece ser a mais promissora para solucionar os desafios interligados com a reutilização desta matéria-prima. Apesar de tudo, é de extrema importância destacar que a borra presente na E5, apenas deverá ser utilizada na formulação de subprodutos que apresentem limites microbiológicos mais flexíveis que os definidos no guia do INSA.
Spent coffee grounds are one of the potential by-products produced by the coffee industry and contain various bioactive compounds, making them an excellent substrate for the development of value-added products. However, the logistical challenges associated with their collection, as well as their rapid microbiological degradation, represent a barrier to preservation and subsequent reuse. In this context, the present study aimed to carry out a comparative analysis of the stability and shelf life of spent coffee grounds stored in five different types of packaging over a period of 15 days. The packaging selected for the study features a set of promising properties for reducing the proliferation of microorganisms and enhancing the durability of the spent coffee grounds, and were as follows: corn starch (E1), kraft paper (E2), kraft paper with 50g of silica gel (E3), kraft paper with 25g of calcium chloride (E4), and vacuum-sealed polyethylene (E5). To meet the proposed objective, 100g of spent coffee grounds, collected after 24 hours of activity in a coffee shop, were placed in each type of packaging, and several physico-chemical parameters (colour, pH, moisture, water activity) and microbiological (microorganisms at 30 ºC and moulds and yeasts) of the stored spent grounds were monitored on days 0, 2, 5, 7, and 15. In parallel, a life cycle analysis was carried out, based on data compiled from the literature, with the aim of assessing the environmental impact associated with each of the packaging materials under study. The results of this project showed that E5 was statistically more effective in preserving the colour and pH parameters, mainly due to the absence of oxygen. E1 and E4 allowed for a greater reduction in moisture and water activity, justified by high-water vapor transmission rate and the desiccant capacity of calcium chloride, respectively. From a microbiological perspective, it was confirmed that the spent coffee grounds have a high initial load of microorganisms at 30 ºC, and in the case of moulds and yeasts, E5 was the most effective in controlling their proliferation over time. The life cycle analysis made it possible to observe that E5 presents a lower environmental footprint for the impact categories considered, mainly due to the fact that the production of kraft paper and corn starch shows high variability and greater pollution potential in certain stages. In conclusion, this study demonstrated a clear correlation between the type of packaging used and the stability of the spent coffee grounds over time, with E5 appearing to be the most promising in addressing the challenges associated with the reuse of this raw material. Nevertheless, it is extremely important to highlight that the spent grounds stored in E5 should only be used in the formulation of by -products that allow more flexible microbiological limits than those defined in the INSA guidelines.
Spent coffee grounds are one of the potential by-products produced by the coffee industry and contain various bioactive compounds, making them an excellent substrate for the development of value-added products. However, the logistical challenges associated with their collection, as well as their rapid microbiological degradation, represent a barrier to preservation and subsequent reuse. In this context, the present study aimed to carry out a comparative analysis of the stability and shelf life of spent coffee grounds stored in five different types of packaging over a period of 15 days. The packaging selected for the study features a set of promising properties for reducing the proliferation of microorganisms and enhancing the durability of the spent coffee grounds, and were as follows: corn starch (E1), kraft paper (E2), kraft paper with 50g of silica gel (E3), kraft paper with 25g of calcium chloride (E4), and vacuum-sealed polyethylene (E5). To meet the proposed objective, 100g of spent coffee grounds, collected after 24 hours of activity in a coffee shop, were placed in each type of packaging, and several physico-chemical parameters (colour, pH, moisture, water activity) and microbiological (microorganisms at 30 ºC and moulds and yeasts) of the stored spent grounds were monitored on days 0, 2, 5, 7, and 15. In parallel, a life cycle analysis was carried out, based on data compiled from the literature, with the aim of assessing the environmental impact associated with each of the packaging materials under study. The results of this project showed that E5 was statistically more effective in preserving the colour and pH parameters, mainly due to the absence of oxygen. E1 and E4 allowed for a greater reduction in moisture and water activity, justified by high-water vapor transmission rate and the desiccant capacity of calcium chloride, respectively. From a microbiological perspective, it was confirmed that the spent coffee grounds have a high initial load of microorganisms at 30 ºC, and in the case of moulds and yeasts, E5 was the most effective in controlling their proliferation over time. The life cycle analysis made it possible to observe that E5 presents a lower environmental footprint for the impact categories considered, mainly due to the fact that the production of kraft paper and corn starch shows high variability and greater pollution potential in certain stages. In conclusion, this study demonstrated a clear correlation between the type of packaging used and the stability of the spent coffee grounds over time, with E5 appearing to be the most promising in addressing the challenges associated with the reuse of this raw material. Nevertheless, it is extremely important to highlight that the spent grounds stored in E5 should only be used in the formulation of by -products that allow more flexible microbiological limits than those defined in the INSA guidelines.
Descrição
Palavras-chave
Borra de café Embalagens ativas Biopolímeros Economia circular Sustentabilidade Spent coffee grounds Active packaging Biopolymers Circular economy Sustainability
Contexto Educativo
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Licença CC
Sem licença CC