This is the insoluble precursor of pectin which when boiled in acid solution such as jelly making is hydrolysed to soluble pectin.
(a) Pectin
(b) Protopectin
(c) Methyl alcohol
(d) Pectic acid
The question was posed to me in an interview for job.
My doubt is from Principles of Food Concentrates-1 topic in division Principles of Food Preservation by Canning and Drying and Principles of Food Concentrates of Food Engineering