Deciphering the role of phenolics and antioxidants in rancidity development of pearl millet flour during storage https://doi.org/10.21276/AATCCReview.2026.14.02.100 Ashok Kumar https://orcid.org/0000-0003-3223-6248 Neelesh Mishra https://orcid.org/0009-0000-5087-0264 Bharath S https://orcid.org/0009-0008-8109-5676 Mallesh Gampa https://orcid.org/0009-0004-1271-8906 Sonal Warkad https://orcid.org/0009-0008-4017-1046 Vinutha, T https://orcid.org/0000-0003-4484-3870 Suneha Goswami https://orcid.org/0000-0002-2113-9963 Sudhir Kumar https://orcid.org/0000-0002-1089-7435 Aditi Kundu https://orcid.org/0000-0002-9623-6311 Sumerpal Singh https://orcid.org/0000-0002-2476-9530 Manjunath Prasad https://orcid.org/0000-0001-9363-4915 Ranjeet R. Kumar https://orcid.org/0000-0002-2279-6340 Pearl millet flour undergoes rapid post-milling rancidity, yet the interplay between lipid deterioration and endogenous antioxidant depletion remains poorly characterized. This study assessed hydrolytic and oxidative rancidity, concurrent with phenolic and antioxidant dynamics, in genotypes Chadi Bajra and MPMH-17 during 60 days of ambient storage. Lipid content declined progressively in both genotypes, from 5.43% to 4.58% in Chadi Bajra and 6.67% to 5.21% in MPMH-17. Acid value increased sharply to 18.16 mg KOH/g and 24.73 mg KOH/g by 30 days, while peroxide value peaked at 43.39 and 70.24 meq/kg, confirming rapid hydrolysis and hydroperoxide formation. Total phenolics decreased substantially (Chadi Bajra: 19.70 to 8.67 mg/100 g; MPMH-17: 16.47 to 5.81 mg/100 g), accompanied by marked reductions in thiols and FRAP activity, indicating progressive antioxidant exhaustion. Correlation and PCA analysis showed that declining antioxidant capacity aligned strongly with rising rancidity markers, with MPMH-17 consistently clustering toward high-deterioration vectors. Collectively, the results demonstrate that rancidity progression is initiated early, driven by coordinated lipid hydrolysis and oxidation, and amplified by depletion of phenolic and thiol-based antioxidants. The pronounced susceptibility of MPMH-17 highlights genotype-dependent biochemical resilience and underscores the need to integrate antioxidant traits when evaluating flour shelf life.

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Original Research Article
Ashok Kumar2 Neelesh Mishra1 Bharath S1 Mallesh Gampa1 Sonal Warkad1 Vinutha, T1 Suneha Goswami1 Sudhir Kumar3 Aditi Kundu4 Sumerpal Singh5 Manjunath Prasad6 Ranjeet R. Kumar7
1 Division of Biochemistry, ICAR–Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
2 ICAR–Indian Agricultural Research Institute, Hazaribagh, Jharkhand 825405, India
3 Division of Plant Physiology, ICAR–Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
4 Division of Agricultural Chemicals, ICAR–Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
5 Division of Genetics, ICAR–Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
6 Division of Seed Science and Technology, ICAR–Indian Agricultural Research Institute (ICAR-IARI), New Delhi 110012, India
7 ICAR–Indian Institute of Millets Research, Hyderabad, Telangana 500030, India
https://doi.org/10.21276/AATCCReview.2026.14.02.100

Abstract

Pearl millet flour undergoes rapid post-milling rancidity, yet the interplay between lipid deterioration and endogenous antioxidant depletion remains poorly characterized. This study assessed hydrolytic and oxidative rancidity, concurrent with phenolic and antioxidant dynamics, in genotypes Chadi Bajra and MPMH-17 during 60 days of ambient storage. Lipid content declined progressively in both genotypes, from 5.43% to 4.58% in Chadi Bajra and 6.67% to 5.21% in MPMH-17. Acid value increased sharply to 18.16 mg KOH/g and 24.73 mg KOH/g by 30 days, while peroxide value peaked at 43.39 and 70.24 meq/kg, confirming rapid hydrolysis and hydroperoxide formation. Total phenolics decreased substantially (Chadi Bajra: 19.70 to 8.67 mg/100 g; MPMH-17: 16.47 to 5.81 mg/100 g), accompanied by marked reductions in thiols and FRAP activity, indicating progressive antioxidant exhaustion. Correlation and PCA analysis showed that declining antioxidant capacity aligned strongly with rising rancidity markers, with MPMH-17 consistently clustering toward high-deterioration vectors. Collectively, the results demonstrate that rancidity progression is initiated early, driven by coordinated lipid hydrolysis and oxidation, and amplified by depletion of phenolic and thiol-based antioxidants. The pronounced susceptibility of MPMH-17 highlights genotype-dependent biochemical resilience and underscores the need to integrate antioxidant traits when evaluating flour shelf life.

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