Highlights
•A novel approach for improved utilization of food industry waste/by-products.
•Industry waste streams selected: grape pomace and broken wheat.
•3D printing for the production of customized foods with improved value.
•Insights for cleaner production and effective resource recovery.
•Optimization of 3D printing conditions in the in-house fabricated printer CARK.
Abstract
Wastes and by-products of the food industry are often overlooked and utilized or underutilized. Of late, the emphasis is being given to recover, recycle, and recondition waste, promoting sustainable food processing.
In this research, grape pomace and broken wheat which are otherwise sent for animal feed were collected from industries and were used as key ingredients of a 3D printing material supply for the production of functional cookies.
The administration of grape pomace augmented the nutritional value and antioxidant properties of the cookies. Printing using a nozzle diameter of 1.28 mm, extruder motor speed of 600 rpm, and print speed of 400 mm/min gave the optimal printability for the in-house developed extrusion-based food 3D printer CARK.
The printed constructs were post-processed at 130 °C for 12 min and the 6% grape pomace formulation received the highest preference during sensory evaluation. Interestingly, the developed product was rich in proteins and dietary fiber.
This approach highlights the potential for value addition of industrial waste streams with good consumer preference. Accordingly, the unmatched levels of customization that additive manufacturing offers can be well complemented with personalizing foods in terms of nutritional content, whilst providing scope for cleaner production practices and improved recovery of resources from food processing wastes.
Conclusion
This study explains a novel and sustainable approach for the utilization of food industry waste streams. Using the 3D printing approach, grape pomace powder-incorporated broken wheat (flour) cookies were prepared.
While it offers the merits of producing foods with customized shapes, the approach can overcome consumer perception of having foods from waste and by-products. An in-house fabricated extrusion printer was used and the printing conditions were optimized.
Consequently, a detailed study on the effect of printing parameters on the different cookie formulations was performed. This further confirmed that an increase in grape content increased the viscosity, thereby resulting in the utilization of lesser print speed, and extrusion rate for improved printability.
Moreover, baking the printed cookies revealed improved structural features, and thus confirming post-processing enhances the shape stability of the printed matrices. Sensory preferences explain that this approach has the potential to produce value-added foods with functional benefits.
While the concept focuses on the ‘waste-to-wealth’ approach, the findings of this research add a new dimension to 3D printing technology. In the future, this study can further be developed by incorporating macro/micronutrients from the under-utilized food sources.
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