Growth Impairment Caused by Raw Linseed Consumption: Can Trypsin Inhibitors Be Harmful for Health?
Linseed (Linun usitatissimum L.) is an important oilseed whose nutritional value can be impaired due to presence of antinutritional factors and low protein digestibility. Protein fractions from raw linseed meal were extracted, isolated and analyzed in vitro and in vivo. Globulins, the major protein fraction of linseed, showed low in vitro susceptibility to trypsin and chymotrypsin, but its in vivo digestibility was 93.2 %. Albumin fraction had high trypsin inhibition activity (5250 Inhibition Units g−1) and presented low molecular mass protein bands, similar to known trypsin inhibitors. Raw linseed consumption caused negative effects on rat growth and reduction of intestinal villi. Results indicate that raw linseed meal must not be used as an exclusive source of protein regardless of the major proteins have high digestibility; digestive enzymes inhibitors in raw linseed probably reduces the protein utilization.
KeywordsLinseed Trypsin inhibitors Globulins Albumins Antinutritional factors Protein digestibility
Group I – casein group
Group II – raw linseed group
Human salivary amylase
Net protein ratio
Protein efficiency ratio
Sodium dodecyl sulphate polyacrylamide gel electrophoresis
Our sincere acknowledgements to Maurício Pereira de Sales, a great researcher and professor (in memoriam). The authors also gratefully acknowledge Ana Heloneida A. Morais and Adriana F. Uchôa for fruitful discussions and generous help. This work was supported by the Brazilian agencies FINEP, CNPq, CAPES and BNB-FUNDECI.
Conflict of Interest
The authors declare no competing financial interest.
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