Commercially important edible nut seeds were analyzed for chemical composition and moisture sorption. Moisture (1.47-9.51%), protein (7.50-21.56%), lipid (42.88-66.71%), ash (1.16-3.28%), total soluble sugars (0.55-3.96%), tannins (0.01-0.88%), and phytate (0.15-0.35%) contents varied considerably. Regardless of the seed type, lipids were mainly composed of mono- and polyunsaturated fatty acids (>75% of the total lipids). Fatty acid composition analysis indicated that oleic acid (C18:1) was the main constituent of monounsaturated lipids in all seed samples. With the exception of macadamia, linoleic acid (C18:2) was the major polyunsaturated fatty acid. In the case of walnuts, in addition to linoleic acid (59.79%) linolenic acid (C18:3) also significantly contributed toward the total polyunsaturated lipids. Amino acid composition analyses indicated lysine (Brazil nut, cashew nut, hazelnut, pine nut, and walnut), sulfur amino acids methionine and cysteine (almond), tryptophan (macadamia, pecan), and threonine (peanut) to be the first limiting amino acid as compared to human (2-5 year old) amino acid requirements. The amino acid composition of the seeds was characterized by the dominance of hydrophobic (range = 37.16-44.54%) and acidic (27.95-33.17%) amino acids followed by basic (16.16-21.17%) and hydrophilic (8.48-11.74%) amino acids. Trypsin inhibitory activity, hemagglutinating activity, and proteolytic activity were not detected in the nut seed samples analyzed. Sorption isotherms (Aw range = 0.08-0.97) indicated a narrow range for monolayer water content (11-29 mg/g of dry matter). No visible mold growth was evident on any of the samples stored at Aw < 0.53 and 25 degrees C for 6 months.

Chemical composition of selected edible nut seeds

A review of composition studies of cultivated almonds: Macronutrients and micronutrients

Response surface optimization of ultrasound-assisted oil extraction from autoclaved almond powder

Fatty acid composition affected by kernel weight in almond [prunus dulcis (mill.) d.a. webb.] genetic resources

The major U.S. marketing varieties of almonds contained moisture, protein, fat, and ash in the range 4.35–5.86%, 16.42–22.17%, 53.59–56.05%, and 2.69–2.93%, respectively. Two fatty acids, oleic (range 52.44–67.07%) and linoleic (range 22.05–38.67%) accounted for up to 90% of the total fat. The majority of almond proteins (≥ 95%) are water soluble with a minimum solubility at pH ≤ 4.0. Sodium chloride (1.0 M) decreased the almond protein solubility in aqueous medium. Electrophoretic analyses indicated that one water soluble protein dominates the almond protein composition. This oligomeric major protein is made up of two kinds of polypeptides (molecular weight range 20,000–22,000 and 38,000–41,000) linked via disulfide bonds. Among the proteases tested, pepsin was the most efficient in hydrolyzing the almond proteins.

Solubilization, electrophoretic characterization and in vitro digestibility of almond (Prunus amygdalus) proteins

A study of amino acids, sugars, and mineral elements is carried out with the sweet almond cultivated in Mallorca (Spain). Seventeen amino acids are determined by ion-exchange liquid-liquid chromatography. Glutamic acid is the most abundant, and the essential amino acids determined constitute 34% by weight of the total amino acids determined. The absence of reducing sugars is noted by several methods, and the content of sucrose is found to be 5.52%. The elements Fe, Ca, K, Na, Mg, Cu, Zn, Mn, P, Co, and Mo are determined by atomic absorption and colorimetric methods. Cobalt and molybdenum have not been previously cited in this fruit by other authors. © 1981 American Chemical Society.

F.S. Calixto

Papers

Amino acids, sugars, and inorganic elements in the sweet almond (Prunus amygdalus).