Development of fermentation method to improve the nutrition value of carob kibble

Abstract

Carob (Ceratonia siliqua L.) is an evergreen tree belonging to the family Leguminosae (subfamily Caesalpiniaceae). Carob kibble contains high concentrations of D-pinitol and phenolic compounds; however it also contains a high level of unhealthy sugar. The main objective of this study was to develop a methodical approach for improving the health-promoting properties of carob kibble and reducing sucrose, fructose and glucose contents. The carob kibble was fermented by Saccharomyces cerevisiaem (SC), Torulaspora delbrueckii (TD) and Lactobacillus plantarum (LP) with and without pre-treatments. The effects of fermentation on total sugar content, D-pinitol content, phenolic composition, antioxidant capacity, and inhibitory activity of a-glucosidase, a-amylase , pancreatic lipase and hyaluronidase were determined. The sugar contents and D-pinitol contents of carob kibble were identified and quantified with ultra-performance liquid chromatography (UPLC) with refractive index detector and gas chromatography-mass spectrometry (GC-MS). TD and SC are the most effective microorganisms for removing approximately 90% of the total sugar content after 15 hours of fermentation. TD was capable of increasing the D-pinitol level by 29 % after 10 hours of fermentation. TD had the greatest effect on improving phenolic composition and antioxidant capacity, and inhibitory activity of the studied enzymes when compared to the other two microorganisms and was selected for the second phase of the study with pre-treatments (roasting, ultrasonic and microwave). Microwave was very effective pre-treatment before fermentation when compared to the roasting and ultrasonic techniques. The reduction in sugar content was greater after pre-treatments compare to the samples without pre-treatments prior to fermentation. The pre-treatments enhanced the ability to reduce sugar and increase biological activities related to health. Fermented carob kibble can be used as an important source of bioactive compounds for the pharmaceutical and food industries.

Date of Award	2022
Original language	English
Supervisor	Vijay Jayasena (Supervisor)