The rapid increase in agricultural waste generation has become a serious global environmental concern, with banana cultivation contributing a significant share of this biomass waste. Global banana production is estimated to be more than 135 million metric tons each year, producing a considerable amount of leftover biomass including pseudo stems, leaves, rachis and blossoms after harvesting. These materials are often discarded or burned, creating environmental issues such as greenhouse gas emissions and deterioration of soil quality. Among these by-products, banana blossom or male bud has gained attention because of its high nutritional value. It contains dietary fiber, proteins, minerals, vitamins, flavonoids and several bioactive compounds known for their antioxidant, antimicrobial and therapeutic properties.
       
Banana (Musa paradisiaca), a member of the family Musaceae, is widely cultivated in tropical and subtropical regions, with India is one of the leading producers of banana worldwide. Banana blossom has traditionally been consumed in several Asian countries because of its nutritional and medicinal properties (Padam et al., 2014; Singh et al., 2020). However, its utilization remains limited due to its high moisture content and rapid perishability. Drying is an effective preservation technique that improves shelf life while retaining nutritional quality, thereby facilitating its incorporation into value-added food products (Padam et al., 2014). Banana blossom is a rich source of dietary fibre, minerals and bioactive compounds with antioxidant potential (Padam et al., 2014; Singh et al., 2020). Besides its traditional medicinal uses, banana blossom has attracted increasing attention as a functional food ingredient because of its potential application as a natural source of dietary fibre, antioxidants and nutraceutical components in value-added food products (Padam et al., 2014).
       
Growing consumer preference for functional and value-added foods has created opportunities for the effective utilization of banana blossom in processed products. Converting banana blossom into stable forms through dehydration can enhance its shelf life and support its incorporation into innovative food formulations. Therefore, considering its nutritional significance and underutilization, efforts have been directed towards developing banana blossom powder and evaluating its application in millet-based extruded products.
       
Millets are small-seeded cereal grains recognized for their high nutritional value and health-promoting properties. Compared with commonly consumed cereals such as rice and wheat, Millets are rich in dietary fibre, protein, minerals and phytochemicals, making them valuable functional food ingredients (Bachate et al., 2025). They are widely recommended for children, pregnant and lactating women, the elderly and individuals with gluten intolerance because of their nutrient density and ease of digestion. Millets play an important role in nutritional security and sustainable agriculture.
       
Among the ingredients used in the present study, amaranth is valued for its superior protein quality, favourable amino acid composition and abundance of minerals and bioactive compounds, making it a suitable ingredient for gluten-free product development (Bachate et al., 2025). Finger millet is an excellent source of calcium, iron and dietary fibre, while foxtail millet contributes protein, minerals and dietary fibre, making both suitable ingredients for nutrient-rich gluten-free products (Bachate et al., 2025). The complementary nutritional composition of these grains, together with banana blossom powder, offers considerable potential for developing nutrient-dense gluten-free extruded snack products with enhanced functional and nutritional properties.
       
Recent research has highlighted the increasing importance of utilizing underexploited agricultural by-products and climate-resilient cereals for the development of sustainable functional foods. Banana blossom has emerged as a promising functional ingredient because of its high dietary fibre, phenolic compounds, essential minerals and antioxidant constituents, making it suitable for the development of value-added food products while simultaneously promoting agricultural waste valorization (Kukreja and Sharma, 2025). Likewise, millets have received considerable attention as nutrient-dense gluten-free grains owing to their high dietary fibre, quality protein, essential minerals and health-promoting phytochemicals, thereby contributing to nutritional security and sustainable food systems (Jacob et al., 2024; Sadh et al., 2024). Furthermore, recent advances in extrusion technology have demonstrated that appropriate processing conditions can improve starch gelatinization, protein digestibility, dietary fibre functionality and overall product quality while producing shelf-stable, consumer-acceptable functional foods (Dey et al., 2024). However, despite these advancements, studies investigating the combined application of banana blossom powder and nutrient-rich millets in gluten-free extruded snack products remain limited, thereby justifying the need for the present investigation.
       
Extrusion is a high-temperature short-time processing technique commonly used for producing cereal-based snacks and ready-to-eat foods. The process involves mixing, cooking, shearing, puffing, shaping and drying under controlled conditions. During extrusion, important changes such as starch gelatinization, protein denaturation and destruction of microorganisms and anti-nutritional factors occur, improving product quality and shelf-life (Robin et al., 2012). Although banana blossom has been investigated as an ingredient in bakery and traditional food products, information regarding its utilization in gluten-free millet-based extruded snacks is limited. Furthermore, studies evaluating the combined influence of banana blossom powder and nutrient-rich millets on the nutritional, mineral and colour characteristics of extruded products are scarce. Therefore, there is a need to develop value-added gluten-free extruded snacks enriched with banana blossom powder to enhance their nutritional quality and functional value.
       
Extrusion cooking is an efficient thermal process that enhances digestibility while maintaining nutritional quality. Water acts as a plasticizer and expansion agent, though excess moisture may reduce puffing and increase product density (Robin et al., 2012; Fellows, 2017). The technology also provides flexibility in developing value-added foods with different shapes, textures and flavors, making it highly suitable for innovative food product development.
       
During extrusion processing, the combined action of high temperature, pressure, moisture and shear forces induces significant physicochemical transformations in food biopolymers. Starch undergoes gelatinization and partial dextrinization, resulting in improved expansion, crisp texture and enhanced digestibility. Simultaneously, protein denaturation and molecular realignment improve protein digestibility and contribute to the formation of a stable product structure. Extrusion also modifies the composition and functionality of dietary fibre by increasing soluble fibre fractions and improving water absorption characteristics, while reducing anti-nutritional compounds through thermal degradation. Furthermore, controlled extrusion conditions promote desirable flavour development and colour formation through Maillard reactions, thereby improving consumer acceptability. These physicochemical modifications play a crucial role in determining the nutritional quality, texture, colour, expansion behaviour and sensory characteristics of gluten-free extruded snack products (Sadh et al., 2024; Jacob et al., 2024).
       
Therefore, the present study was undertaken to develop gluten-free millet-based extruded snacks incorporated with banana blossom powder and to evaluate their proximate composition, dietary fibre, mineral composition and colour characteristics.

The present investigation was carried out during 2025-2026 at the College of Food Technology, Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani, Maharashtra, India. Fresh banana blossoms (Musa paradisiaca L., Grand Naine variety) were procured from a local banana orchard in Parbhani, Maharashtra. Amaranth (Amaranthus spp.), finger millet (Eleusine coracana), foxtail millet (Setaria italica) and corn flour were purchased from the local market of Parbhani. All raw materials were cleaned manually to remove foreign matter, damaged grains and other impurities before processing. Potassium metabisulphite (KMS) and all analytical-grade chemicals and reagents used for physicochemical and mineral analyses were procured from HiMedia Laboratories Pvt. Ltd., Mumbai, India.
 
Preparation of banana blossom powder
 
Fresh banana blossoms contained an initial moisture content of approximately 89-91% (wet basis), which necessitated drying to improve storage stability, facilitate milling and prevent microbial spoilage. After pretreatment, the slices were dried in a tray dryer at 60°C until a constant weight was achieved. This drying temperature was selected because it provides an optimum balance between efficient moisture removal and the retention of nutritional and bioactive compounds, while minimizing excessive enzymatic browning and thermal degradation of heat-sensitive constituents. Drying at moderate temperatures has been reported to preserve the colour, phenolic compounds and functional properties of banana blossom more effectively than higher drying temperatures, thereby improving the quality of the resulting powder.
       
Banana blossom powder was prepared with slight modifications to the method described by Anand and Sharma (2019). Fresh banana blossoms (Musa paradisiaca L., Grand Naine variety) were washed thoroughly under running tap water to remove adhering dirt and impurities. The outer bracts and non-edible portions were manually removed and the edible florets were separated. The florets were cut into slices of approximately 3-5 mm thickness and immediately immersed in a 750 ppm potassium metabisulphite (KMS) solution for 15 min to minimize enzymatic browning.
       
After pretreatment, the slices were drained and spread uniformly in a single layer on stainless-steel trays. Drying was carried out in a cabinet tray dryer (Osaw Industrial Products Pvt. Ltd., Ambala, India, Model: JSGW-CTD at 60±2°C for 5-7 h until a constant weight was obtained. The dried slices were cooled to room temperature (27±2°C) and ground using a laboratory grinder (Make: Retsch, Model: ZM 200). The resulting powder was sieved through an 80-mesh (180 μm, U.S. Standard Sieve) stainless-steel sieve to obtain a uniform particle size.
       
The banana blossom powder was packed in low-density polyethylene (LDPE) pouches, sealed using a heat sealer and stored at ambient temperature (25-27°C) in a dry place until further analysis and use in the preparation of the extruded products.
 
Preparation of roasted millet flour (Amaranth, foxtail and finger)
 
Roasting of millets was done with slight modifications as per the method used by Bachate et al., (2025). Amaranth, finger millet and foxtail millet grains were cleaned separately and roasted in oven toaster griller (OTG), Model: Majesty 4500 TMCSS, oven at 120°C for 10 min. Cooled it to room temperature grind and sieve it 220 μ (70 mesh sieve) and stored in LDPE bag for further processing and analysis purpose.
 
Preparation of extruded product
 
Composite gluten-free flour blends were prepared by mixing corn flour, banana blossom powder, roasted amaranth flour, finger millet flour and foxtail millet flour in different proportions on a dry weight basis as presented in Table 1. The formulation of each treatment was designed to evaluate the effect of increasing levels of banana blossom powder on the nutritional and colour characteristics of the extruded products while maintaining acceptable processing and sensory properties. All dry ingredients were weighed accurately and blended uniformly using a ribbon blender to obtain a homogeneous composite flour mixture. The prepared blends were stored in low-density polyethylene (LDPE) pouches at ambient temperature until extrusion processing.


       
The formulation of the composite flour blends was developed based on preliminary extrusion trials and previous reports on gluten-free extruded products to achieve improved nutritional quality, functional characteristics and consumer acceptability.
       
Five formulations consisting of a control and four treatment combinations were prepared by incorporating banana blossom powder at different levels while maintaining the millet flour blend as the base ingredient. The formulations were developed to evaluate the influence of banana blossom incorporation on the nutritional, mineral, colour and sensory characteristics of gluten-free extruded snacks. Following extrusion, all formulations were subjected to sensory evaluation using a 9-point hedonic scale. The formulation exhibiting the highest overall acceptability together with desirable nutritional and physical characteristics was considered the optimum formulation for subsequent evaluation and discussion.
 
Extrusion process and parameters for development of extruded product incorporated with banana blossom powder
 
Extrusion processing was carried out at the Millet Processing and Incubation Centre, Professor Jayashankar Telangana State Agricultural University (PJTSAU), Hyderabad, Telangana, India. The prepared composite flour blends were conditioned to a moisture content of 10-12% prior to extrusion and processed using a co-rotating, fully intermeshing twin-screw extruder (KK-FSC65, KK Life Science, Chennai, India). The extruder was equipped with a feed hopper, mixing section and three independently controlled barrel temperature zones. Extrusion was performed under the processing conditions presented in Table 2. The extruded products emerging from the 4 mm die opening were cut using a rotating knife assembly operating at 2800 rpm, cooled to room temperature and packed in low-density polyethylene (LDPE) pouches for subsequent physicochemical, mineral and colour analyses.


 
Proximate and mineral composition analysis
 
The proximate composition and mineral content of the extruded product incorporated with banana blossom powder were analysed using standard AOAC (2019) methods. Moisture, crude fat, protein, fibre, ash and carbohydrate contents were determined to evaluate the nutritional quality. The mineral profile, including calcium, phosphorus, iron, magnesium, potassium, zinc, copper, was evaluated.
 
Determination of dietary fiber
 
Total dietary fiber was estimated from samples using AOAC (2019) method. Sample (1g) was taken in Erlenmeyer flask, 25 ml of 0.1 M sodium phosphate buffer (pH 6.0) added to suspended sample. The sample was incubated in boiling water bath for 15 min and cooled. Then 20 ml of distilled water added and pH adjusted to 1.5 with 4N hydrochloric acid. Pepsin (100 mg) was added and incubated at 40°C with agitation for 60 min. Then it was cooled and 20 ml distilled water added and pH was adjusted to 6.8 with 4 N sodium hydroxide. Thereafter 100 mg pancreatic enzyme was added and incubated at 40°C with agitation for 60 min. Then the resultant decanted through filter paper.
 
Insoluble dietary fiber (IDF)
 
The residue was washed with 2 × 10 ml of 95 % ethanol and acetone, dried at 105°C to constant weight. The sample is then transferred to weighed crucible (D1) and kept for incineration in muffle furnace at 550°C for 5 hrs. After cooling weight of crucible noted (C1).
 
Soluble dietary fiber (SDF)
 
The volume of filtrate was made up to 100 ml and 400 ml of warm 95% ethanol added to it. The solution was then kept for 1 hr to precipitate, then filtered thoroughly and dried. The sample was added with 2 × 10 ml of 95% ethanol and acetone. The washed sample was then kept for drying at 105°C. After drying it was then transferred to a weighed crucible (D2). The crucible was incinerated in muffle furnace at 550°C for 5 hrs. After cooling weight of crucible noted (C2).
 
Colour analysis
 
Banana blossom powder incorporated extruded product were subjected to colour measurement. The change of colour was measured and compared using hunter lab colo flex EZ colorimeter (Hunter Associates Laboratory Inc., Reston, Virginia, USA). Among the three-color coordinates, namely L*, a* and b*, ‘‘L*’’ represents the lightness index, ‘‘a*’’ represents red-green, while ‘‘b*’’ represents yellow-blue colour components. The measurement of L*, a* and b* values of colour was carried out in triplicate and the average values were reported (Mala et al., 2016).
 
Statistical analysis
 
The experiment was conducted using a completely randomized design (CRD) with all analyses performed in triplicate. The experimental data were expressed as mean ±standard deviation and subjected to analysis of variance (ANOVA) to determine significant differences among treatments. Treatment means were compared using the critical difference (CD) test at the 5% level of significance (P≤0.05) following the procedure described by Panse and Sukhatme (1985). Statistical analyses were performed using OPSTAT statistical software.

Proximate composition of extruded product incorporated with banana blossom powder
 
The proximate composition of banana blossom powder incorporated gluten-free extruded products is presented in Table 3. The incorporation of banana blossom powder significantly (P≤0.05) influenced the nutritional composition of the developed products. An increasing trend was observed for moisture, protein, ash and dietary fibre contents, whereas carbohydrate and fat contents decreased progressively with increasing levels of banana blossom powder. These changes indicate that banana blossom powder served as an effective functional ingredient for improving the nutritional quality of the extruded snacks.


       
The moisture content increased from 6.00% in the control (T₀) to 7.70% in treatment T₄. The increase may be attributed to the high water-binding capacity of the dietary fibre present in banana blossom powder, which enhances moisture retention during extrusion processing. Similar observations have been reported by Padam et al., (2014) and Singh et al., (2020). In contrast, carbohydrate content showed a gradual decline with increasing banana blossom powder incorporation because the fibre- and mineral-rich banana blossom replaced a portion of the starch-rich cereal ingredients in the formulation.
       
Protein content increased gradually from 11.79% in the control to 13.17% in T₄, indicating the nutritional contribution of banana blossom and the complementary protein supplied by amaranth and millet flours. Conversely, fat content decreased slightly with increasing banana blossom powder levels, which is advantageous for the development of healthier snack products with lower lipid content. Similar improvements in nutritional quality have been reported for fibre-enriched food products (Padam et al., 2014; Singh et al., 2020).
       
Dietary fibre was markedly enhanced following banana blossom powder incorporation. Soluble dietary fibre increased significantly in the fortified formulations compared with the control, although its concentration varied among treatments, possibly due to extrusion-induced structural modifications of dietary fibre. In contrast, insoluble dietary fibre generally increased with increasing banana blossom powder incorporation. Increased dietary fibre intake is associated with improved gastrointestinal health, better glycaemic control and enhanced satiety (Anderson et al., 2009). Ash content also increased progressively with fortification, indicating enrichment of the products with essential minerals naturally present in banana blossom (Singh et al., 2020). The incorporation of banana blossom powder significantly enhanced the dietary fibre content of the extruded snacks compared with the control formulation due to its naturally high fibre composition. In addition to increasing the total dietary fibre content, extrusion processing may alter the physicochemical characteristics of dietary fibre by partially converting insoluble dietary fibre into soluble dietary fibre through the disruption of plant cell wall polysaccharides under high temperature and shear conditions. This structural modification improves the water-holding capacity, hydration properties and physiological functionality of dietary fibre without substantially reducing the overall fibre content.
       
Among the developed formulations, T₂ (10% banana blossom powder) exhibited the most desirable nutritional profile by providing improved protein, dietary fibre and mineral content while maintaining acceptable carbohydrate, fat and moisture levels. Therefore, T₂ was identified as the optimum formulation for the development of nutritionally enriched gluten-free extruded snacks.
 
Mineral composition of extruded product incorporated with banana blossom powder
 
The mineral composition of banana blossom powder incorporated gluten-free extruded products is presented in Table 4. Incorporation of banana blossom powder significantly (P≤0.05) enhanced the mineral profile of the developed products, demonstrating its effectiveness as a natural source of essential micronutrients. Progressive increases were observed in calcium, phosphorus, zinc and magnesium contents with increasing levels of banana blossom powder, whereas iron and copper showed slight variations among treatments. Potassium content varied among the formulations without exhibiting a consistent increasing trend. Nevertheless, all treatments retained appreciable amounts of potassium, indicating that the extrusion process preserved this essential electrolyte despite differences in formulation composition. These changes reflect the naturally mineral-rich composition of banana blossom and indicate its suitability as a fortifying ingredient for the development of nutrient-dense gluten-free extruded snacks.


       
Calcium and phosphorus contents increased progressively with increasing banana blossom powder incorporation, indicating improved mineral enrichment of the extruded products. These minerals are essential for bone mineralization, skeletal development and normal metabolic functions. Similarly, zinc and magnesium contents also increased steadily, suggesting that banana blossom powder contributed valuable micronutrients involved in immune function, enzyme activation, protein synthesis and energy metabolism. Comparable improvements in mineral composition following banana blossom incorporation have been reported by Sheng et al., (2010) and Singh et al., (2020).
       
Iron content increased substantially in the fortified treatments, reaching its highest value in T₃, followed by a slight decline in T₄. The variation may be attributed to mineral interactions during extrusion processing and differences in ingredient proportions among formulations. Copper content exhibited comparatively greater variability, which may be associated with the heterogeneous distribution of trace minerals in the composite flour blends. Nevertheless, all fortified treatments contained higher concentrations of essential minerals than the control, indicating the nutritional advantage of banana blossom powder fortification (Gharibzahedi and Jafari, 2017). Among the developed formulations, T₂ provided a well-balanced mineral composition while maintaining overall product quality and acceptability. These findings demonstrate that banana blossom powder can be successfully utilized as a natural fortifying ingredient for the production of nutritionally enriched gluten-free extruded snack products with enhanced mineral value.
 
Colour characteristics of banana blossom powder incorporated gluten-free extruded products
 
The colour characteristics of the developed gluten-free extruded products are presented in Table 5. Incorporation of banana blossom powder significantly influenced the colour attributes of the products, as reflected by the CIE Lab* colour values. Progressive incorporation of banana blossom powder resulted in decreased lightness (L*) and yellowness (b*), whereas the redness (a*) values showed only minor variations among treatments. These changes are primarily attributed to the natural pigments present in banana blossom and the thermal reactions occurring during extrusion processing.


       
The L* value decreased progressively from the control to the highest level of banana blossom powder incorporation, indicating gradual darkening of the extruded products. This reduction in lightness may be attributed to the presence of polyphenolic compounds and anthocyanin pigments in banana blossom, together with non-enzymatic browning reactions such as the Maillard reaction and caramelization during extrusion processing (Pathare et al., 2013; Fellows, 2017).
       
The a* values exhibited only slight variation among treatments, indicating that banana blossom powder had a limited effect on product redness. In contrast, the b* values gradually decreased with increasing levels of banana blossom powder, suggesting a reduction in yellowness due to pigment degradation and the formation of darker coloured compounds during thermal processing. Similar changes in colour characteristics have been reported for fibre-enriched extruded products and banana-based food formulations (Pathare et al., 2013; Singh et al., 2020).
       
Among the developed formulations, T₂ exhibited the most desirable colour characteristics by maintaining acceptable lightness while retaining favourable redness and yellowness values. Therefore, T₂ was considered the optimum formulation, providing a suitable balance between improved nutritional quality and consumer-acceptable appearance.
 
Texture profile analysis of BBP-based extruded products
 
Table 6 presents the texture profile analysis (TPA) of the control (T₀) and the optimized banana blossom powder-incorporated extruded snack (T₂). Incorporation of 10% banana blossom powder significantly influenced the textural characteristics of the product. The hardness increased from 2802.00 g in the control to 5474.00 g in T₂, indicating the formation of a denser and more compact structure due to the high dietary fibre content of banana blossom powder, which restricts starch expansion during extrusion. Conversely, cohesiveness decreased from 0.29 to 0.17, suggesting reduced internal structural integrity associated with fibre incorporation. Gumminess showed a slight increase from 802.00 g to 953.00 g, reflecting the combined effect of increased hardness and reduced cohesiveness. Springiness decreased from 2.61 mm in the control to 1.82 mm in T₂, indicating a reduction in elastic recovery of the extrudates. A slight increase in adhesiveness was observed in T₂ (0.50 mJ) compared to the control (0.00 mJ), which attributed to the presence of soluble fibre and other hydrophilic components in banana blossom powder.

The present study demonstrated that banana blossom powder can be successfully incorporated into gluten-free millet-based extruded products to enhance their nutritional and functional quality. Increasing levels of banana blossom powder significantly improved the protein, dietary fibre, ash and mineral contents of the developed products while producing acceptable colour characteristics. The incorporation of banana blossom powder also contributed to the development of value-added extruded snacks with enhanced nutritional properties, highlighting its potential as a functional food ingredient and an effective means of utilizing an underexploited agricultural resource. Among the developed formulations, T₂ (10% banana blossom powder incorporation) exhibited the most desirable balance between nutritional improvement, mineral enrichment and acceptable colour characteristics, making it the optimum formulation for product development. The findings of this study suggest that banana blossom powder has considerable potential for application in the formulation of nutritious gluten-free extruded snack products and may contribute to the development of sustainable, health-oriented functional foods. Further studies may focus on storage stability, consumer acceptability and large-scale commercial production of the developed products.

The authors sincerely acknowledge the College of Food Technology, Vasantrao Naik Marathwada Krishi Vidyapeeth (VNMKV), Parbhani, Maharashtra, India, for providing the necessary laboratory facilities and infrastructure to carry out this research. The authors also express their sincere gratitude to the faculty members and laboratory staff for their valuable guidance, technical assistance and continuous support throughout the course of the study.

Disclaimer
 
The views and opinions expressed in this manuscript are those of the authors and do not necessarily reflect the views of the affiliated institution or the publisher.

The authors declare no conflict of interest.