From a professional point of view, the concept of pectinase is too broad, because the structure of pectin is complex. The enzyme that can hydrolyze the glycosidic bond of galacturonic acid polysaccharide α- 1 4 can be called pectinase, and the enzyme that can destroy the secondary complex main chains such as RG-I and RG-II can also be called pectinase. Pectin contains a large number of neutral sugar side chains, and may also contain different quantities and types of polyphenols and protein (depending on the source of pectin). After the popularization of science, I began to answer the landlord's questions.

Pectin cannot be digested by human body (small intestine and stomach) for two main reasons:

First, the molecular weight of pectin is large enough, and the molecular weight of pectin from different sources ranges from hundreds of thousands to millions of Da, which makes it difficult for water-soluble pectin and water-insoluble pectin to be quickly dissolved in human digestive juice. Stomach is an important organ for human body to digest food, and gastric acid creates a low pH environment to hydrolyze most foods. Insoluble pectin is difficult to fully contact with acid solution and hydrolyze (of course, pectin with large molecular weight can also resist acid hydrolysis to a certain extent. After all, many pectins are extracted by acid, but research shows that long-term immersion in acid solution can indeed degrade neutral sugar side chains of pectin to some extent). In addition, even if part of pectin can be acidified, it takes a lot of time. The gastric emptying period of human body is short, which is far from the time for pectin digestion and acidolysis, so pectin cannot be digested by stomach, and of course, chemical corrosion of stomach is useless.

Secondly, the research shows that no matter human saliva, gastric juice, pancreatic juice or intestinal juice, there are not enough enzymes that destroy the structural integrity of pectin (pectin structure refers to the first paragraph of popular science, and the types of enzymes also refer to the first paragraph), so it cannot be digested by human stomach.

It is worth noting that pectin is not indigestible by human body, because enzymes secreted by some bacteria in colon can digest and decompose pectin, so the landlord's question is not rigorous, so my answer specially emphasizes that pectin cannot be digested by human stomach and small intestine. Let's look at science. Pectin drugs on the market now, such as bismuth pectin, are actually realized by using the characteristics of colon-specific release of pectin.

Hope to adopt, thank you ~