Development of gluten free crackers using water chestnut (Trapa natans) and Pearl Millet (Pennisetum glaucum)

Introduction

Crackers are types of crisp baked products, chemically leavened or fermented Bakery is the rapid growing segment of gluten-free products, due to increasing availability of gluten-free flour alternatives.^[1] The baking industry faces significant challenges in producing gluten-free products due to concerns over gluten intolerance and sensitivity. To address this, various underutilized food sources like buckwheat, amaranth, quinoa, and water chestnut, which are rich in starch and antioxidants, have been studied for incorporation into bakery products. Additionally, there's a growing demand for low glycemic index (GI) bakery products, especially among diabetic individuals, hence exploration of low GI food sources and innovative ingredients, along with modifications to baking and post-baking processes, is necessary. Some authors have suggested freezing and frozen storage as a method to potentially reduce GI in baked goods.^[2]

Water chestnut, abundant in South East Asia, China, and Northern India cultivated from November to March, offers a rich source of gluten-free starch. Its flour can replace wheat flour in producing gluten-free products, with the potential for novel applications due to alterations in structure and functional properties during flour production. Extracts from water chestnut have shown high inhibitory activity against glycolytic enzymes, making them effective in managing type-2 diabetes by reducing blood glucose elevation and insulin secretion. Water chestnut flour is promising for developing low glycemic index bakery products.^[3], ^[4], ^[5]

Pearl millet, originating from the West African grass and domesticated in the Saharan Desert, expanded its cultivation to East Africa and later to India. India's substantial contribution to pearl millet production, amounting to 44% of global millet production, highlights its importance. This grain, rich in iron and zinc, presents a cost-effective solution to address micronutrient deficiencies in regions where millet consumption is prevalent. Moreover, pearl millet's protein content, ranging from 9 to 21%, is comparable to wheat but surpasses that of sorghum, rice, and maize. Furthermore, pearl millet stands out as a mineral powerhouse, boasting significant amounts of iron, zinc, magnesium, copper, manganese, potassium, and phosphorus. While mature kernels are abundant in vitamin A, they lack vitamins B and C, yet contain valuable bioactive compounds such as phenolics. Recognizing the pivotal role of nutrition in both preventing communicable and non-communicable diseases underscores the significance of harnessing pearl millet's nutritional potential for the preparation of nutrient-dense foods.^[6], ^[7], ^[8], ^[9], ^[10]

Objectives

To Formulate crackers using Pearl millet

To enrich the product by incorporating water chestnut flour

To determine the Sensory quality of the developed product

To Estimate the Proximate composition and cost of the developed product

Method of preparation

The process involved mixing all ingredients with oil-coated hands to achieve a crumb-like texture. Water was gradually added to form smooth dough, which was then allowed to rest for 30 minutes. The dough was shaped into small balls, flattened evenly, pricked and cut into desired shapes, and baked in a preheated oven at 200°C for 10-12 minutes until light brown and crisp. Once cooled, the crackers were stored in an airtight container.

Proximate analysis of water chestnut crackers

The nutritional profile of the product underwent analysis following A.O.A.C. (2005) methodologies. Moisture content was determined via hot air oven drying at temperatures ranging from 98 to 100°C. Protein content was assessed using the Micro-Kjeldhal method to measure total nitrogen. Ash percentage was determined through high-temperature incineration in a muffle furnace, while fat content was estimated using the Soxhlet apparatus. Crude fiber content was analyzed using a crude fiber analyzer. Carbohydrate content was calculated by deducting the sum of moisture, protein, fat, and ash from 100, based on a 100g sample. Additionally, mineral concentrations, including calcium, iron, and phosphorus, were quantified using Atomic Absorption Spectrometry (AAS). ^[12]

Results and discussion   

Proximate composition of water chestnut crackers

The proximate composition of the chosen PMC4 and the control were undertaken for analysis and the findings are outlined in [Table 3]. Notably, the moisture content remained constant across all variations of PMC. Intriguingly, PMC4 demonstrated elevated protein content in comparison to the control, accompanied by a slight reduction in carbohydrate fiber content. Additionally, PMC4 exhibited increased levels of essential nutrients, including phosphorus and calcium as well.

Nutrients	Control	Variation 4 (PMC4)
Energy (kcal)	376.19±0.13	384.32±0.12*
Carbohydrate (g)	63.74±0.16	63.31±0.09
Protein (g)	10.35±0.11	11.88±0.05*
Fat (g)	8.87±0.23	9.28±0.14*
Fibre (g)	9.09±0.17*	7.46±0.21
Moisture (%)	5.12±0.10	5.09±0.16
Ash (g)	2.83±0.06	2.98±0.18
Iron (mg)	3.51±0.18	3.36±0.24
Phosphorus (mg)	255.73±0.20	310.53±0.19*
Calcium (mg)	30.1±0.17	48.56±0.23*

Table 3 Proximate composition of Water Chestnut crackers, values are mean ± SD (n=3) *p value ≤ 0.05 (Holm Sidak method).

Conclusion

The study aimed to develop nutrient rich, gluten-free crackers for individuals with celiac disease using pearl millet flour and water chestnut flour. Among the variations tested, PMC4 emerged as the most preferred interms of sensory properties, showcasing superior nutritional composition. Phosphorus and calcium content was drastically increased with incorporation of water chestnut flour and is gluten free with replacement of wheat flour with pearl millet flour and was also rich in protein content. Overall the development of gluten Free Crackers using Water Chestnut and pearl millet flour was superior in terms of sensory and nutritional aspects on par with the control.

Source of Funding

None.

Conflict of Interest

None.