Nutritional, Functional, and Technological Outcomes of Fortification Strategies in Unleavened Bakery Products: A Systematic Review

Abstract

Unleavened bakery products—breadsticks, crackers, taralli, and flatbreads—are widely consumed and represent promising carriers for nutritional fortification. Studies have explored adding dietary fibers, plant proteins, phytochemicals, vitamins, minerals, and agro- industrial by- products, but findings remain scattered. We systematically reviewed studies on fortification strategies for unleavened bakery products, searching PubMed, MEDLINE, Embase, Ovid, and Web of Science without time restrictions (last search 20 August 2025). Two reviewers independently conducted screening, data extraction, and quality appraisal. Risk of bias was assessed with validated and adapted tools according to design, and certainty of evidence with GRADE. Ninety- seven studies met inclusion criteria: 88 experimental laboratory studies, 7 randomized controlled trials, 1 cross- sectional survey, and 1 ani mal feeding trial. The most frequently investigated ingredient macrocategories were Cereals & Bran by- products (24.7%), Wine & Olive by- products (18.6%), and Plant skins & Extracts (18.6%). Marked heterogeneity precluded meta- analysis; evidence was synthesized narratively. Fortification—typically involving substitution levels between 5% and 30% of wheat flour with legume flours, pseudo- cereals, or plant by- products—increased fiber, phenolics, micronutrients, and antioxidant capacity, while improving or maintaining physical and textural properties and overall acceptability. Human trials were few and brief, showing mixed effects on glycemia, satiety, and cardiometabolic markers; bioavailability and dose–response were seldom tested. Gaps included poor reporting of processing parameters, small samples, inconsistent sensory and shelf- life evaluation, and scarcity of clinically meaningful endpoints. This review provides the first comprehensive synthesis of fortification approaches for unleavened bakery products, consolidates the evidence base, and identifies priorities: standardized analytical and sensory protocols, assessment of shelf- life and consumer acceptance, nutrient bioavailability, and powered clinical studies aligned with public- health nutrition and product innovation.