219: Upcycling Concord Grape Pomace Into a Shelf-Stable Fruit Spread

Introduction

Concord grape pomace (CGP), a byproduct of the juice and wine industries, offers a significant opportunity for sustainable innovation. It is rich in bioactive compounds, dietary fiber, and antioxidants, offering feasible options for upcycling into a shelf-stable fruit spread, addressing economic and environmental challenges while meeting consumer demand for healthier, high-fiber products.

Methods

The spread was formulated evaluating 4 concentrations of freeze-dried and ground CGP (12%, 15%, 18%, 20%) and 3 stabilizers at 1 and 2% (pectin, citrus fiber, inulin-pea protein conjugate) in water for best consistency. The 18% CGP with 1% pectin was selected for shelf-studies. To balance the sweetness, sugar, Concord grape concentrate, and a mix of 50% each were evaluated at 8.6% dry solids addition. Final spreads were hot packed in glass canning jars at 82°C to achieve shelf stability. Samples were analyzed for total soluble solids, color, pH, titratable acidity, viscosity, total phenolics, monomeric anthocyanins and antioxidant activity (DDPH and ABTS) at 0, 2, 4, and 6 months of storage at 20°C. Proximate composition and sensory evaluation (n=93) were performed to assess consumer acceptability. Studies were conducted in triplicate.

Results

The best consistency was achieved when formulating with 18% CGP, 12.6% Concord grape concentrate and 1% pectin (6760 ± 150 mPa×s viscosity and 87% water holding capacity), offering a clean label product. Changes in pH, acidity, viscosity, and total soluble solids were minimal over the 6-month study.

Color changes in a* values (from 8.3 ±0.3 to 7.6 ±0.3) and L* values (from 31.9 ±0.2 to 33.5 ±0.1) reflected significant (p < 0.05) losses in anthocyanins over time (~50%) while total phenolic content and antioxidant capacity showed higher retention (~85%). Sensory evaluation revealed good consumer acceptance, particularly for the spread sweetened with Concord grape juice concentrate, which was ranked higher and had higher purchase intent (p < 0.05).

Significance

Concord grape pomace can be effectively transformed into a nutritious, clean label, and shelf-stable fruit spread, supporting sustainable food production and innovation.

Authors: Emerson Villalta, Viral Shukla, Mark Emile H. Punzalan, Olga I. Padilla-Zakour