Valorisation of pumpkin seeds through wheat-sorghum-pumpkin seed composite flour muffins: optimization using D-optimal mixture design

Abstract

Interest in the use of composite flours for baked products to enhance nutrition, increase the health benefit and diversify utilization of by-products is rising. This study was conducted to determine the effect of proportion of wheat, germinated sorghum and pumpkin seed flour on flour functional properties and physicochemical and sensory properties of muffins using D-optimal mixture design. The water absorption index (WAI), oil absorption index (OAI) and swelling index (SWI) were significantly (p < 0.05) influenced by the blend proportions whereas bulk density (BD) was not significantly influenced. The protein content increased with increase in the proportion of pumpkin seed flour. The fiber content increased with increase in the proportion of sorghum and pumpkin seed flour. The sensory scores decreased with increase in the proportion of sorghum and pumpkin seed flour. Preferred results were found using up to 10% pumpkin seed flour and up to 21% sorghum flour. Using numerical optimization, a combination of 83% wheat flour, 10% pumpkin seed flour and 7% sorghum flour gave best results with a desirability value of 0.621. Pumpkin seed flour can be incorporated up 10% and sorghum flour up to 7% for an acceptable product.

Keywords:

• Valorization
• optimization
• pumpkin seeds
• mixture design

REVIEWING EDITOR:

• M. Luisa Escudero-Gilete, University of Seville, Spain

SUBJECTS:

• Agriculture and Food; Food Additives & Ingredients; Food Analysis; Food Engineering; Food Manufacturing & Related Industries

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Hlengiwe Mdluli

Hlengiwe Mdluli a graduate in Food Science Nutrition and Technolgy from the University of Eswatini.

Solomon W. Kidane

Prof. Solomon W. Kidane is a professor in Food Process Engineering at the University of Eswatini. His research area includes food rheology, food process modelling and optimization and product development.

T. P. Nkambule

Dr T.P. Nkambule is a senior lecturer. Her research area includes food safety, food microbiology, food preservation, food quality assurance, among others.

J. S. Shelembe

Dr J.S. Shelembe is a Lecturer, and his research area includes food chemistry, product development, food processing and preservation technologies.