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Abstract(s)
A gestão eficiente de resíduos é uma prática de extrema relevância quando se pretende alcançar a sustentabilidade ambiental na indústria alimentar. No setor dos laticínios, a produção de requeijão origina o sorelho, gerado em quantidades significativas e que atualmente não tem aproveitamento. Representa, portanto, uma particular preocupação pela sua elevada carga orgânica, que faz com que o seu tratamento seja bastante difícil, bem como pela sua elevada CQO (Carência Química de Oxigénio), CBO (Carência Biológica de Oxigénio) e CBO5 (Carência Bioquímica de Oxigénio em cinco dias), que implicam bastantes prejuízos a nível ambiental. Esta problemática é acentuada na zona da Serra da Estrela pela incidência de pequenas empresas de cariz tradicional sem capacidade de tratamento e gestão dos efluentes gerados. Neste projeto pretende-se valorizar este resíduo através da fermentação, convertendo a lactose em ácido lático, o qual será posteriormente recuperado por um processo de extração. Para cumprir este objetivo foi promovida a fermentação com as espécies Lactococcus lactis (Lc. lactis), Lactobacillus casei (Lb. casei) e com estas duas espécies em consórcio, tendo o melhor resultado sido alcançado com o Lb. casei com o consumo completo da lactose no meio preparado com sorelho. Foram produzidas 24.56 g/L de L- ácido lático a partir de 17.46 g/L de lactose por esta bactéria, o que representou um rendimento do processo de 138 %, com um rendimento de 1.45 g/ácido lático produzido por g/lactose consumida. A técnica salting out foi selecionada para promover a extração do ácido lático, sendo a fase orgânica constituída por etanol e a inorgânica pelo sal hidrogenofosfato dipotássico (K2HPO4). Alcançou-se uma eficiência de 77 % no processo extração do ácido lático da solução obtida a partir do meio de fermentação e de 66 % após a etapa de purificação com carvão ativado. Por fim, procedeu-se à concentração da amostra por evaporação a pressão reduzida a uma temperatura de 48 ºC, obtendose um composto de elevada viscosidade com uma concentração de 35 % deste ácido orgânico. Os resultados alcançados revelaram uma possibilidade de conversão do resíduo sorelho num subproduto e da consequente redução do impacto ambiental associado à produção do requeijão.
An efficient waste management is a very relevant practice when trying l to achieve food industry environmental sustainability. In the dairy industry, second cheese whey is a curd cheese waste generated in significative amounts, which is currently a highly underappreciated resource. It represents a particular concern due to its high organic matter which leads to a very difficult treatment, as well as for its high COD (Chemical Oxygen Demand), BOD (Biological Oxygen Demand) and BOD5 (Biological Oxygen Demand in five days), which involves considerable environmental loss. This is a sharp problem in the area of Serra da Estrela due to the traditional small companies’ incidence with no ability to achieve an efficient waste management. This project aims to value this waste through the fermentation, converting lactose in to lactic acid, which is subsequently recovered through an extraction process. To achieve this goal, the fermentation was carried out with the species Lactococcus lactis (Lc. lactis), Lactobacullis casei (Lb. casei) and the mixing of both species, with the best outcome being achieved by the Lb. casei with the complete consumption of the lactose in the fermentation broth prepared with second cheese whey. 24.56 g/L of L-lactic acid were produced from 17.46 g/L of lactose by this bacterium, which represented a yield of 138%, and 1.45 g/ of lactic acid produced per g/ of consumed lactose. The salting out technique was selected to perform the lactic acid extraction, with ethanol as the organic phase and dipotassium hydrogen phosphate (K2HPO4) as the inorganic phase. An efficiency of 77% was achieved by the extraction process of lactic acid from the fermentation broth medium and an efficiency 66% after the purification process with activated carbon. Finally, the concentration of the resulting sample was achieved by evaporation in reduced pressure conditions at 48 ºC. A high viscosity compound was obtained with a 35 % concentration of this organic acid. The achieved results revealed the possibility of converting this residue into a by-product and the consequent environmental impact reduction of the curd cheese production.
An efficient waste management is a very relevant practice when trying l to achieve food industry environmental sustainability. In the dairy industry, second cheese whey is a curd cheese waste generated in significative amounts, which is currently a highly underappreciated resource. It represents a particular concern due to its high organic matter which leads to a very difficult treatment, as well as for its high COD (Chemical Oxygen Demand), BOD (Biological Oxygen Demand) and BOD5 (Biological Oxygen Demand in five days), which involves considerable environmental loss. This is a sharp problem in the area of Serra da Estrela due to the traditional small companies’ incidence with no ability to achieve an efficient waste management. This project aims to value this waste through the fermentation, converting lactose in to lactic acid, which is subsequently recovered through an extraction process. To achieve this goal, the fermentation was carried out with the species Lactococcus lactis (Lc. lactis), Lactobacullis casei (Lb. casei) and the mixing of both species, with the best outcome being achieved by the Lb. casei with the complete consumption of the lactose in the fermentation broth prepared with second cheese whey. 24.56 g/L of L-lactic acid were produced from 17.46 g/L of lactose by this bacterium, which represented a yield of 138%, and 1.45 g/ of lactic acid produced per g/ of consumed lactose. The salting out technique was selected to perform the lactic acid extraction, with ethanol as the organic phase and dipotassium hydrogen phosphate (K2HPO4) as the inorganic phase. An efficiency of 77% was achieved by the extraction process of lactic acid from the fermentation broth medium and an efficiency 66% after the purification process with activated carbon. Finally, the concentration of the resulting sample was achieved by evaporation in reduced pressure conditions at 48 ºC. A high viscosity compound was obtained with a 35 % concentration of this organic acid. The achieved results revealed the possibility of converting this residue into a by-product and the consequent environmental impact reduction of the curd cheese production.
Description
Keywords
Sorelho Sustentabilidade ambiental Ácido lático Second cheese whey Environmental sustainability Lactic acid