{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T05:04:22Z","timestamp":1776402262347,"version":"3.51.2"},"reference-count":53,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2023,8,7]],"date-time":"2023-08-07T00:00:00Z","timestamp":1691366400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Japan Science and Technology Agency","award":["JPMJTR194A"],"award-info":[{"award-number":["JPMJTR194A"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>The rice endosperm protein (REP) hydrolysate containing the following rice endosperm protein derived oligopeptides QQFLPEGQSQSQK, LPEGQSQSQK, and pEQFLPEGQSQSQK (a N-terminal pyroglutamate residue-modified peptide) reportedly showed an antidepressant-like effect in an animal model. We investigated the effect of the REP hydrolysate on healthy humans who self-reported mental fatigue with subjectively low vigor. Seventy-six participants (age: 20\u201364 years) were randomly allocated to two groups. The influence of the REP hydrolysate on the mood state was evaluated in two studies: single intake (Study 1) and repeated intake over 4 weeks (Study 2). A salivary stress marker, Chromogranin A (CgA), was measured in Study 1. The single intake of the REP hydrolysate significantly improved the Profile of Mood Status 2nd edition for adults (POMS 2) subscale of Tension\u2013Anxiety. Additionally, the salivary CgA concentrations were remarkably reduced after the single intake of the REP hydrolysate. Though a single intake of the REP hydrolysate did not significantly influence the other subscales and the TMD of the POMS 2 and the Euthymia Scale, both the subjective and objective results supported the possible effect of the REP hydrolysate on reducing anxiety and nervousness. No significant positive effects on the subjective mood state (Euthymia Scale and POMS 2) and sleep quality (Insomnia Severity Index) were observed in the trial setting employed for Study 2. In conclusion, a single intake of REP hydrolysate might help relax the subjective feelings of tension and anxiety. The effectiveness of repeated REP hydrolysate intake needs to be tested in a different clinical setting.<\/jats:p>","DOI":"10.3390\/nu15153491","type":"journal-article","created":{"date-parts":[[2023,8,8]],"date-time":"2023-08-08T12:38:59Z","timestamp":1691498339000},"page":"3491","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["The Effect of the Rice Endosperm Protein Hydrolysate on the Subjective Negative Mood Status in Healthy Humans: A Randomized, Double-Blind, and Placebo-Controlled Clinical Trial"],"prefix":"10.3390","volume":"15","author":[{"given":"Ryoko","family":"Nakayama","sequence":"first","affiliation":[{"name":"Rice Research Institute, Kameda Seika Co., Ltd., Niigata 950-0198, Niigata, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9349-3294","authenticated-orcid":false,"given":"Daisuke","family":"Nishi","sequence":"additional","affiliation":[{"name":"Department of Mental Health, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masaru","family":"Sato","sequence":"additional","affiliation":[{"name":"Department of Applied Genomics, Kazusa DNA Research Institute, 2-6-7 Kazusakamatari, Kisarazu 292-0818, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Akira","family":"Ito","sequence":"additional","affiliation":[{"name":"Rice Research Institute, Kameda Seika Co., Ltd., Niigata 950-0198, Niigata, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kimiko","family":"Uchiyama","sequence":"additional","affiliation":[{"name":"Rice Research Institute, Kameda Seika Co., Ltd., Niigata 950-0198, Niigata, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7757-9514","authenticated-orcid":false,"given":"Yuki","family":"Higuchi","sequence":"additional","affiliation":[{"name":"Rice Research Institute, Kameda Seika Co., Ltd., Niigata 950-0198, Niigata, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hajime","family":"Takahashi","sequence":"additional","affiliation":[{"name":"Rice Research Institute, Kameda Seika Co., Ltd., Niigata 950-0198, Niigata, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9944-8635","authenticated-orcid":false,"given":"Kousaku","family":"Ohinata","sequence":"additional","affiliation":[{"name":"Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011, Kyoto, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,8,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1111\/nyas.12540","article-title":"An Overview of Global Rice Production, Supply, Trade, and Consumption","volume":"1324","author":"Muthayya","year":"2014","journal-title":"Ann. 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