Extracts of Hechtia spp. as Novel Coagulants Reduce the Pollutant Load of Whey

Traditional coagulant calf rennet, which is used in cheese production, is currently facing the problem of an unsustainable source. In addition, the production of cheese with calf rennet produces whey with high biochemical (BOD) and chemical oxygen demand (COD) values. For these reasons, plant extracts have been investigated as sustainable sources of coagulants for milk. However, there are few reports on the changes in the COD and BOD of whey when plant extracts are used. For this reason, this study investigated the potential of extracts from two Hechtia species native to Mexico ( H. glomerata and H. podantha ) as sustainable milk coagulants for cheese production, with the aim of simultaneously reducing the pollutant load of residual whey. The milk coagulation efficiency of the extracts of the two Hechtia species was investigated, and in addition, their effects on cheese texture and color, and the composition of the residual whey, including BOD and COD, were evaluated. Most extracts of H. podantha showed adequate milk coagulation and yielded fresh cheese with textural properties comparable to those of cheese produced with conventional calf rennet. A significant reduction in carbohydrate content was achieved when H. podantha extracts were used. As a result, a significant decrease in the BOD and COD values was achieved. In some cases, a reduction of up to 1.78 times compared with those of the control was achieved. The results of this study show that H. podantha is a promising source of natural coagulants for sustainable cheese production, offering a dual benefit by providing an alternative to conventional rennet and reducing the environmental impact of whey.