An Alfalfa Protein Concentrate from Four Cultivars at Three Growth Stages¹

Abstract

New sources of high quality protein are needed for human consumption. Alfalfa (Medicago sativa L.) is well known for its high yield of protein. Knowledge of genetic variation for protein concentrate yield among cultivars is needed. The alfalfa cultivars ‘Dawson’, ‘Kanza’, ‘Team’, and ‘Weevlchek’ were planted in field plots at the Mead Field Laboratory, Lead, Nebr., in 1972. Forage of the cultivars was harvested and sampled as three growth stages, bud, one‐tenth bloom, and full bloom, in the first and second cuttings of 1973. Forage samples were used for chemical analyses of fresh forage, pressing juice in the laboratory, protein extraction, and subsequent chemical analyses. The purposes of the study were to determine the yield of an alfalfa protein concentrate (without chloroplasts) (APC) from four cultivars at three growth stages, the forage yield and quality of fresh forage, and to determine the recovery and nutrient levels in the residue of processed forage. The cultivars did not differ in dry matter,protein,and carotene levels of fresh forage at any growth stage in either the first or second cutting. The percentage of protein in APC's did not differ among cultivars at any growth stage in either cutting and averaged 76%. Forage and APC yields differed among Cultivars. The lowest forage and APC yields were obtained from Kanza. About 1% of the fresh weight of alfalfa was recovered as APC. APC yield averaged about 200 kg/ha over cultivars and cuttings. APC recovery percentages differed among cultivars and the lowest recovery was from Kanza. Protein recovery decreased as physiologic mauturity increased. At one‐tenth bloom, average protein level of fresh forage was 18.6% compared with 16.4% protein in the residue after pressing (juice extraction), a 12% reduction due to processing. Average carotene level of fresh forage was 190 mg/kg, and carotene level of the residue was 145 mg/kg at one‐tcnth bloom, a 24% reduction. The yield of an alfalfa protein concentrate that contained 76% protein, potentially suitable for human consumption, vaned among cultivars as shown in this preliminary study.

Composition of Leaf Protein Concentrate and Deproteinized Juice from Alfalfa, Red Clover, and Birdsfoot Trefoil1

“…Harvest date effects on PC N concentration were very small for alfalfa (Tables 1 and 3). The observed uniformity in alfalfa PC N concentration is in agreement with the findings of Kehr et al ( 1979) with the same species. Red clover PC varied most between harvest dates in N concentration compared with the other species (Table 3).…”

“…Although alfalfa has been widely studied for mechanical dewatering (Oelshlegel et al, 1969;Jorgensen, 1977;Kehr et al, 1979), two other important perennial legumes, red clover (Trifolium pratense L.) and birdsfoot trefoil (Lotus corniculatus L.), have not been fully evaluated. Also, the importance of maturity stage on component yield and composition needs further study.…”

Control of Smoothseed Alfalfa Dodder (Cuscuta approximata) in Alfalfa (Medicago sativa)

“…In fourth year, the hay yield varied between 1823 and 3007 kg/ha in dodder-free control parcels and the dodder-infested parcels, respectively. The values for the raw protein ratio in 2011 and 2012 were within the expected range (15.6-23.3%) and close to each other (Kehr et al, 1979;Acikgoz, 2001). The raw protein ratio was below the expected level for each of the applications in the fourth year of the study, except for the control parcels without dodder.…”

Expression of alfalfa juice

“…Dry matter recovery in the press cake, 54-62%, was lower than that reported by Bruhn and Koegel (1974), 76%, by Knuckles et al (1970), 66-81 %, or by Kehr et al (1979), 80%; thus, that in the press juice was higher.…”