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Impact of processing on the protein quality of a pinto bean/buckwheat blend, as determined by in vitro and in vivo methodologies
Author(s) -
Nosworthy Matthew G,
Franczyk Adam,
Neufeld Jason,
House James D
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.893.8
Subject(s) - casein , protein efficiency ratio , chemistry , food science , protein quality , protein digestibility , pinto bean , digestion (alchemy) , limiting , soy protein , pea protein , extrusion , wheat flour , extrusion cooking , zoology , feed conversion ratio , biology , chromatography , botany , body weight , phaseolus , materials science , starch , mechanical engineering , endocrinology , engineering , metallurgy
Blending of multiple protein sources can increase protein quality by compensating for limiting amino acids present in the individual sources. Processing flour by extrusion and baking can also alter the quality of a protein. In order to determine the effect of processing and blending on flours from buckwheat (BW) and pinto beans (PB), a rodent bioassay was performed. S prague ‐ Dawley rats (n=100, ~70 g) were randomized to one of ten diets (10% crude protein): casein (reference control) or one of 3 experimental groups: untreated, extruded or baked (simulated baked cracker flour; SBCF) with either PB, BW or a 50:50 pinto bean/buckwheat blend (PB/BW). The protein efficiency ratio (PER), true protein digestibility (TPD%) and protein digestibility corrected amino acid score (PDCAAS) were calculated. The relationship between (TPD%) and in vitro digestibility was also investigated. The in vitro digestibility of the protein sources was determined via enzymatic digestion and subsequent pH drop. PER estimation was not possible for untreated PB or PB/BW blends. Extrusion did not alter the PER of BW flour (extruded 2.96 ± 0.31, untreated 2.89 ± 0.17) however, the PER of SBCF BW was lower than the other BW diets (1.81 ± 0.45, p<0.05).Extruded PB had significantly lower PER (1.67 ± 0.25) than either casein (2.83 ± 0.14) or extruded BW (p<0.05).SBCF PB had the lowest PER of any diet studied (1.26 ± 0.52, p<0.05). Extruded PB/BW had a significant increase in PER over extruded PB alone (2.48 ± 0.16, p<0.05), however the extruded PB/BW had a lower PER than extruded BW (p<0.05).Extrusion increased the digestibility of BW flour (p<0.05), while extruded PB/BW had a significantly higher digestibility than extruded BW (p<0.05).SBCF treatment reduced the digestibility of both BW and PB flours compared to either controls or extruded products (p<0.05), while the SBCF PB/BW was more digestible than either SBCF BW or SBCF PB. Interestingly, a correlation was found between the digestibility values calculated through the rodent bioassay and in vitro method (R 2 = .6718, p=0.0128).A similar correlation was found between PDCAAS and the in vitro digestibility corrected amino acid score (R 2 =0.9280, p=.0001). Overall, extruded products had higher PER values, increased digestibility and greater PDCAAS values than SBCF products with the extruded PB/BW having the greatest PDCAAS value of the experimental diets. As a strong correlation was found between both digestibility and PDCAAS values generated from in vitro and in vivo methods, the use of in vitro digestibility analysis should be investigated as a potential replacement for the current rodent assay for nutrient content claim purposes. Support or Funding Information Manitoba Agri‐Health Research Network; Saskatchewan Pulse Growers; AAFC Growing Forward II; Global Institute for Food Security