Determination of the protein quality of almonds (Prunus dulcis L.) as assessed by in vitro and in vivo methodologies

Abstract

Almonds (Prunus dulcis), such as all nuts, are positioned within the protein foods grouping within the current U.S. Dietary Guidelines. The ability to make claims related to the protein content of almonds, within the United States, requires substantiation via the use of the Protein Digestibility‐Corrected Amino Acid Score (PDCAAS). The present study was designed to provide current estimates of PDCAAS, using both in vivo and in vitro assays, of key almond varietals from the 2017 California harvest. Additionally, historical protein and amino acid composition data on 73 separate analyses, performed from 2000 to 2014, were analyzed. Amino acid analysis confirmed lysine as the first‐limiting amino acid, generating amino acid scores of 0.53, 0.52, 0.49, and 0.56 for Butte, Independence, Monterey, and Nonpareil varietals, respectively. True fecal protein digestibility coefficients ranged from 85.7% to 89.9% yielding PDCAAS values of 44.3–47.8, being highest for Nonpareil. Similar, albeit lower, results were obtained from the in vitro assessment protocol. Analysis of the historical data again positioned lysine as the limiting amino acid and yielded information on the natural variability present within the protein and amino acid profiles of almonds. Comparison of the 2017 AA profile, averaged across almond varietals, to the historical data provided strong evidence of persistence of amino acid composition and indices of protein quality over time.

Environmental Impacts of Foods in the Adventist Health Study-2 Dietary Questionnaire

“…Our estimate of water consumption for nuts and seeds was higher than a published estimate for almonds [51], but this is reasonable given the significant variation in water consumption associated with almonds even within California alone [53]. We used a land use value for almonds that was per kilogram of protein as a comparison for our nuts and seeds category and converted it to a per kilogram of edible weight value using the assumption that it was 21.2% protein by weight [50,54]. Our water consumption estimate for meats, poultry, and fish was higher than the comparison range.…”

Gastrointestinally Digested Protein from the Insect Alphitobius diaperinus Stimulates a Different Intestinal Secretome than Beef or Almond, Producing a Differential Response in Food Intake in Rats

“…Of the indices that evaluate protein quality in relation to digestibility, one of the most widely adopted is the protein digestibility corrected amino acid score (PDCAAS) [54]. Raw almond has been classified with a PDCAAS value of around 45 [55] and beef with a value of 92 [56], approaching the maximum of 100. Little is known in this regard for insect species, and each species has very different particularities.…”

Review about Non-Lipid Components and Minor Fat-Soluble Bioactive Compounds of Almond Kernel

“…Ahrens et al [ 45 ] found that methionine together with cysteine was the limiting amino acid, followed by lysine and threonine. More recently, House et al [ 68 ] considered that Ahrens et al had underestimated the total sulfur AA content due to a method issue. They found lysine as the limiting AA.…”