Scientists, led by Dipayan Sarkar of the University of Massachusetts, analysed the pulp and skin of two varieties of pear, Starkrimson and Bartlett.
They investigated whether whole pear juice fermented with Lactobacillus helveticus (L. helveticus) could have probiotic benefits by inhibiting growth of Helicobacter pylori (H. pylori) and promoting Bifidobacterium longum (B. longum).
B. longum is a beneficial probiotic which has lactic acid bacteria-like properties while H. pylori, previously known as campylobacter pylori is a pathogen.
The scientists also evaluated the phenolic content for potential management of type 2 diabetes and hypertension.
Co-author Kalidas Shetty said, "It's exciting to explore the potential that pears can have to balance beneficial bacterial activity in the digestive process, as gut health helps support overall health of the body."
“These pear cultivars could also be involved in strategic dietary strategies for better management of early stage hyperglycemia and hypertension.”
The peel and pulp of each variety was extracted using distilled water and 12% ethanol, and the researchers found that peel extracts had a significantly higher phenolic content than pulp extract (900–1300 μg compared with 100–150 μg).
Antioxidant activity was significantly higher in peel than pulp extracts for both varieties (50-70% compared with 20-40%).
To evaluate the probiotic function 100ml of frozen L. helveticus was inoculated and incubated for 24 hours. The researchers added pear juice to the culture and then spread it on H.pylori. Water was used as a control.
Both varieties showed H. pylori inhibition at 48 and 72 hours, while fermented sample of Starkrimson even showed inhibition at 24 h. Neither extract inhibited growth of B. longum.
The researchers suggested the phenolic compounds present in the fermented extracts - including catechin and quercetin derivatives - may be responsible for H. pylori inhibition under acidic conditions.
Phenolic and antioxidant content varies widely among the 3000 varieties of pear that exist, and can also depend on maturity and storage conditions.
Source: Food Research International
Published online 2015 vol. 69 pp. 80–90 doi.org/10.1016/j.foodres.2014.12.014
Dietary functional benefits of Bartlett and Starkrimson pears for potential management of hyperglycemia, hypertension and ulcer bacteria Helicobacter pylori while supporting beneficial probiotic
Authors : D. Sarkar, C.Ankolekar et al.