Formulation, Rheological Characterization and Sensory Evaluation of Jam and Jelly from Annona squamosa L. (Custard apple)

Abstract

Annona Squamosa L. (Custard apple) is a tropical fruit known for its sweet taste, distinct flavour, and pleasant, aromatic creamy pulp. The fruit has high nutritional value as it is rich in protein, carbohydrate, sugars, vitamins, phosphorus, potassium and high dietary fibre with high post-harvest losses and limited utilization in processed food products. There are abundant research on common fruit based products but there is a lack of studies on formulation, standardization and rheological properties which are essential for understanding texture, stability and processing conditions remains largely unexplored. Addressing this gap, an attempt has been taken to formulate custard apple based products like jam and jelly from custard apple pulp and studies of their rheological properties. Custard apple jam and jelly developed with 50% (w/w) sucrose, 0.75% (w/w) commercial high methoxyl content-HCM pectin and 0.5% (w/w) citric acid have overall good acceptability with respect to other composition of jam. The shear rate for all custard apple products (pulp, jam and jelly) ranged between 61.15 S-1 to 183.5 S-1. The Bingham model resulted yield stress for custard apple pulp, jam and jelly as 25.1 dyn/cm2, 38.8 dyn/cm2 and 10.2 dyn/cm2 respectively. The Power law model resulted in consistency index (k) for pulp, jam and jelly as 1442 cP, 1221 cP and 775 cP respectively with a flow index (n) of 0.154, 0.333 and 0.194 respectively. The processed products were found stable for a period of nine months without off-flavour and discolouration.