Sorption isotherms modeling approach of rice-based instant soup mix stored under controlled temperature and humidity

Abstract

Moisture sorption isotherms of rice-based instant soup mix at temperature range 15–45°C and relative humidity from 0.11 to 0.86 were determined using the standard gravimetric static method. The experimental sorption curves were fitted by five equations: Chung-Pfost, GAB, Henderson, Kuhn, and Oswin. The sorption isotherms of soup mix decreased with increasing temperature, exhibited type II behavior according to BET classification. The GAB, Henderson, Kuhn, and Oswin models were found to be the most suitable for describing the sorption curves. The isosteric heat of sorption of water was determined from the equilibrium data at different temperatures. It decreased as moisture content increased and was found to be a polynomial function of moisture content. The study has provided information and data useful in large-scale commercial production of soup and have great importance to combat the problem of protein-energy malnutrition in underdeveloped and developing countries.

Keywords:

• sorption isotherm
• modeling
• soup
• rice
• Moringa oleifera

Public Interest Statement

Rice-based instant soup mix belongs to a class of food powders that is hygroscopic by nature. Moisture sorption isotherms have an important role to play in the quantitative approach to the prediction of the shelf life of dried foods due to their sensitivity to moisture changes. Equations for fitting water sorption isotherms in foods are important in aspects of food preservation by dehydration, packaging, and storage life of a food product. Moisture sorption isotherms of rice-based instant soup mix obtained in the temperature range of 15–45°C were sigmoid type II, common to most foods. Compatibilities of food items can be explored, which are to be packaged together, can be determined with good reliability.

Competing interests

The authors declare no competing interest.

Acknowledgment

The first author acknowledges the receipt of fellowship from Sant Longowal Institute of Engineering and Technology (Deemed University), Longowal during his Doctoral studies.

Additional information

Funding

Funding. The authors received no direct funding for this research.

Notes on contributors

Yogender Singh

Yogender Singh is a postdoctoral fellow and conducted his doctoral research on studies on development of rice-based functional instant soup mix at Sant Longowal Institute of Engineering and Technology, Sangrur, Punjab, India.

Kamlesh Prasad

Kamlesh Prasad is a professor at Sant Longowal Institute of Engineering and Technology, Sangrur, Punjab, India with specialization in engineering properties of foods, fruits and vegetable processing, and non-destructive analysis of biomaterials.