Integral use of grape: Clarified juice production by microfiltration and pomace flour by freeze-drying. Development of gluten-free filled cookies

Abstract

Viticulture is a millenary activity, with winemaking as its primary purpose. Traditionally, by-products have been discarded or underutilized. This study explored a comprehensive use of the grape, which are rich in simple carbohydrates, vitamin C, minerals, and phenolic compounds. A filtration process involving a filter and microfiltration with membranes was employed to clarify the fruit juice. This resulted in a clear, transparent juice with reduced sugar and protein content. Meanwhile, the main by-product, the pomace which is a mixture of skin, seeds, and stalks, also contains a high content of phenolic compounds and fiber, was freeze-dried. In this context, various hydrocolloids were studied for their effectiveness in producing a powder with the desired characteristics. The grape flour obtained was characterized and used in the formulation of gluten free cookies and their filling. The sweet filled cookies exhibited higher protein, vegetable fat, and fiber content than the control cookies and were well-received in sensory evaluations. Therefore, utilizing these flours in food formulations represents an excellent opportunity to valorize waste and enhance the value of the wine industry.

Keywords

• Grape
• Juice
• Microfiltration
• Pomace
• Freeze-drying
• Gluten-free