Impact of Nutritional and Organoleptic Use of Underutilized Green Leafy Vegetables in Bakery Products: A Systematic Review of Novel Food Applications.

Underutilised green leafy vegetable (uglv): an overview

UGLVs are a diverse group of plants that have been historically overlooked in mainstream agriculture but are now gaining attention for their nutritional and medicinal properties. These vegetables are rich in essential nutrients and bioactive compounds, making them valuable for enhancing dietary diversity and addressing nutritional deficiencies in the diet. Many green, leafy vegetables are important for rural folk, as they are a major part of their diet and nutrition. These vegetables, once held in high esteem for their nutritional and medicinal benefits, are now underutilized and unexplored due to changing dietary preferences, lack of awareness, and modern agricultural practices favouring commercially popular crops. The present study aimed to compare the growth and yield performance of different underutilized green leafy vegetables. The growth performance analysis revealed the maximum plant height, leaf breadth, number of leaves per plant, leaf length, leaf area, and yield in different vegetable varieties. Centella asiatica (L.) Urb. is an important medicinal herb and a nutraceutical herb that accumulates highly pentacyclic triterpenoid saponins, an active compound that induces cell rejuvenation to promote physical and mental health (Bhavithra et al., 2019). Other purposes for which Centella asiatica is used include being a green leafy vegetable for juice, drinks, and food preparation. Ipomoea aquatica Forsk. is a common green leafy vegetable grown throughout Southeast Asia. It is a rich source of vitamins, minerals, proteins, fiber, carotenoids, and flavonoids, which bestow various health benefits (Joshi & Chaturvedi, 2013). Although it is a common weed in lakes and freshwater ponds, it is often overlooked because of the lack of knowledge about this green leafy vegetable. Chench (Corchorus acutangulus Lam.) is an unexploited and underutilized leafy vegetable in India (Kurrey et al., 2018). It is a good source of nutrients, including water, energy, protein, fat, carbohydrates, fiber, calcium, phosphorus, iron, and ascorbic acid. The yummiest bitterness in Corchorus leaves is due to the presence of Corchorin glycosides. The growth of green leafy vegetables is highly dependent on several influencing contextual factors, such as the locality's environmental features, climatic conditions, and agronomic activities conducted in that area (Kurrey et al., 2018). A concept or logic model should be designed for the digital information management of green leafy vegetable production, allowing for the implementation of information management systems, including the safety monitoring of green leafy vegetables through barcodes (Shen et al., 2007).

Bakery products can be markedly improved in their mineral and fiber contents by using green leafy vegetables such as spinach, chard, and kale. For example, the mineral content has been enhanced by spinach and chard, while the fiber content has been enhanced with other vegetables, such as onions and pak choi (Santamaria et al., 2023). Various studies have focused on developing value-added products using these underutilized leaves (Joshi & Mathur, 2015; Khatoniar et al., 2018). Although the integration of these underutilized grains and their ingredients shows great promise, consumers must still accept these products, and consistency in product quality must be assured. Therefore, further research should focus on the formulation and processing of novel bakery solutions.

Attributes of included studies

The selection criteria are summarized in Table 3. Of the 24 selected studies, 15 were published in the last ten years and five were studies examining the impact of GLVs on the nutritional profile and sensory attributes, and four evaluated the nutritional and organoleptic properties of underutilized green leafy vegetables. The studies were conducted in several countries, including India, China, the USA, and other European countries, and were published between 2005 and 2025 (Gupta et al., 2005; Sarkar et al., 2023).

Attributes of excluded studies

Studies that did not present experimental data were excluded as a criterion by which the merit of the study findings could be judged. Furthermore, studies lacking proper control groups were excluded to allow reliable comparisons between test and control samples. Participants who considered underutilized green leafy vegetables but had no specific inclinations about their application in bakery products were also excluded. Furthermore, studies that did not include any nutritional analysis or sensory evaluation were excluded, as these were essential to show the effect of GLVs on bakery formulations. Articles published before ten years were excluded. There were 50 studies rejected on these grounds.

Advancement in nutrition bioactive component

The incorporation of underutilized green leafy vegetables (GLVs) into baked goods significantly increased the levels of dietary fiber, vitamins (A, C, E, K, and B-complex), minerals (iron, calcium, and zinc), and bioactive compounds (polyphenols, flavonoids, and carotenoids). Several studies have reported that the addition of GLVs enhances the antioxidant properties of bakery products, thereby contributing to their functional value. For instance, GLV-enriched bakery products exhibited 30–50% higher total phenolic content and antioxidant activity compared to their conventional counterparts (Sarkar et al., 2023).

Assessment of Sensory Context and Consumer Perception: Although improvements in nutritional quality have been observed, sensory attributes such as bitterness, color, and texture remain critical determinants of consumer acceptability. The overall mean acceptability scores across six studies ranged from 6.5 to 8.2 on a 10-point hedonic scale. To address these sensory challenges, various studies have recommended processing techniques such as dehydration and fermentation to reduce undesirable characteristics, as supported by Coppock et al. (1952) and Naqash et al. (2017).

Challenges of technical feasibility and processing

The major technological challenges associated with the incorporation of underutilized green leafy vegetables (GLVs) into bakery formulations include alterations in dough rheology, texture, and shelf-life stability. The addition of GLV powders influences moisture absorption behavior, thereby affecting dough elasticity and crumb structure. Processing techniques such as fermentation and controlled oxidative treatments can improve texture and palatability. Additionally, drying methods, including hot air drying and freeze drying, are effective in preserving bioactive compounds while maintaining desirable sensory attributes. These technological observations have been reported by Belokurova et al. (2015) and Menaka et al. (2024).

Study quality evaluation and limitations

Quality assessment based on the Newcastle-Ottawa Scale (NOS) showed that the included studies had scores ranging between 6 and 9, most being medium to high grade. However, heterogeneity in study designs, GLV types, processing methods, and analytic techniques precluded a feasible quantitative synthesis or meta-analysis.

In summary, according to 10 out of 24 studies, the incorporation of GLVs improved the nutritional and functional properties of bakery products, while 14 did not show a significant difference. Owing to the different methodologies and experimental protocols, complete quantitative synthesis is not possible.

Strengths and limitations

This systematic review was conducted according to the PRISMA guidelines. It followed comprehensive and systematic procedures for the selection and analysis of the literature. Research from four major databases (PubMed, Scopus, Web of Science, and Google Scholar) was included in this study, regardless of the language. This negates the possibility of a publication bias. This synthesis evaluates the nutritional and sensory aspects of the improvements brought by incorporating underutilized green leafy vegetables into baked products, thereby functioning as functional foods. The findings will also contribute to the emerging field of sustainable nutrition by positing underutilized GLVs as contributors to greater dietary diversity.

However, this review has some limitations. Most of the studies included were either observational or experimental, making it difficult to establish a direct causation between GLV incorporation and direct health outcomes. Diverse designs, processing methods, and analytic techniques did not permit a meta-analysis in this study. In addition, biases could arise from differences in sensory evaluation methods and consumer acceptability assessments, as these are mainly self-reported. However, it does not investigate the long-term stability or commercial acceptability of GLV-laden bakery products. Future studies must standardize the formulas and employ randomized controlled trials for functional and sensory validation in real-life implementation contexts.