The Almond (Prunus dulcis): Chemical Properties, Utilization, and Valorization of Coproducts

Almonds ( Prunus dulcis) are one of the most consumed tree-nuts worldwide, with commercial production in arid environments such as California, Spain, and Australia. The high consumption of almonds is partly due to their versatile usage in products such as gluten-free flour and dairy alternatives as well as them being a source of protein in vegetarian diets. They contain high concentrations of health-promoting compounds such as Vitamin E and have demonstrated benefits for reducing the risk of cardiovascular disease and improving vascular health. In addition, almonds are the least allergenic tree nut and contain minute quantities of cyanogenic glycosides. Production has increased significantly in the past two decades with 3.12 billion pounds of kernel meat produced in California alone in 2020 (USDA 2021), leading to a new emphasis on the valorization of the coproducts (e.g., hulls, shells, skins, and blanch water). This article presents a review of the chemical composition of almond kernels (e.g., macro and micronutrients, phenolic compounds, cyanogenic glycosides, and allergens) and the current research exploring the valorization of almond coproducts. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Cyanogenic glycosides content as graft compatibility indicator in pear/quince combinations

The objective of this work is to evaluate the concentration of cyanogenic glycosides CGs (amygdalin and prunasin) in the cultivar and rootstock, as an indicator of compatibility in pear grafts. The work consists of two experiments. Experiment 1 evaluated Cascatense/Pyrus Calleryana and Cascatense/EMC combinations. Experiment 2 evaluated the combinations Packham’s Triumph/Adams, Santa Maria/Adams, and Rocha/Adams. The experimental design of the two experiments was randomized blocks with four replications. The evaluations were carried out in the spring and summer of the harvest 2014/2015. The results indicated graft compatibility in the Cascatense/P. Calleryana, Packham’s Triumph/Adams, and Rocha/Adams combinations; slight incompatibility of Santa Maria/Adams, and severe incompatibility of Cascatense/EMC. The obtained results indicate that differences ≥ 20 mg g-1 of CGs between scion and rootstock were correlated with a drastic reduction in vigor, problems of continuity in graft union, low yield, and early defoliation.

Cyanogenesis in Aralia spinosa (Araliaceae)

A systematic survey of Aralia spinosa (Araliaceae), covering an entire growing season and including aboveground organs at various developmental stages, revealed that only about half of all samples collected showed cyanogenesis. Cyanogenesis was detected in inflorescences and leaves but is apparently restricted to certain harvest times or developmental stages. The structurally unusual triglochinin, characterized by a hex-2-enedioic acid partial structure, was the only cyanogenic glycoside detected. This is the first description of triglochinin in this species and in the family of Araliaceae. Triglochinin is biogenetically derived from tyrosine, which is in good agreement with the few cyanogenic glycosides previously detected in members of the Araliaceae family. Triglochinin was identified, characterized, and quantified by modern chromatographic methods, and the amount of enzymatically releasable hydrocyanic acid was determined qualitatively and quantitatively. Two isomers of triglochinin were detected chromatographically at minor levels. The isomeric pattern agreed well with literature data from other triglochinin-containing plants. This was confirmed in the two species, Triglochin maritima and Thalictrum aquilegiifolium, which were comparatively studied. In the case of A. spinosa, inflorescence buds harvested in July showed the highest content of triglochinin, just under 0.2% on a dry weight basis. The detection of triglochinin adds to the knowledge of toxicological properties and the dereplication of U(H)PLC/MS² data provides a comprehensive phytochemical profile of A. spinosa.

Proximate Analysis and Phytochemical Screening of Triclisia subcordata Oliv Leaf

Proximate analysis and phytochemical screening of Triclisia subcordata Oliv leaf were investigated using standard analytical methods. Results of the proximate analysis showed contents for moisture (79.28±2.32%), ash (1.91±0.21%), crude fibre (1.83±0.13%), lipid (1.81±0.16%), crude protein (8.32±1.20%) and carbohydrate (6.91±0.74%). Phytochemical screening showed the presence of all six metabolites studied but at different concentrations. Saponin and flavonoids > alkaloids > phenol, tannin and cyanogenic glycoside. Tannins, saponins, alkaloids, flavonoids, cyanogenic glycosides and phenol gave 0.01±0.00%, 5.81±0.23%, 2.32±0.13%, 6.01±0.36%, 0.20±0.00% and 0.03±0.00%. Given observed high contents of moisture, flavonoids and saponins, moderate amounts of alkaloids and low contents of lipid, cyanogenic glycosides, tannins and phenols in Triclisia subcordata Oliv leaf, this study rationalises the medicinal use of the plant, and unveils its potential as a source of micronutrients.

Hepatotoxic Effects of Ethanolic leaf Extract of Breynia nivosa (Snow bush) in Wistar rats

The hepatotoxic effects of ethanolic leaf extract of Breynia nivosa in male albino Wistar rats were studied. The Breynia nivosa leaves were extracted using 70% ethanol. The phytochemicals were evaluated and found to contain – tannin, flavonoids, saponins, cardiac glycosides and cyanogenic glycosides. Twenty (20) adult male albino Wistar rats were randomly divided into four (4) groups – three tests of A, B, C and one control – and were administered with 400mg/kg, 200mg/kg and 100mg/kg of the ethanolic leaf extract of Breynia nivosa respectively for 21days after two weeks of acclimatization. The animals were sacrificed under anaesthesia after the experiment and blood samples collected for determination of the antioxidant enzymes (superoxide dismutase and glutathione peroxidase), malondialdehyde, and liver enzyme: aspartate transaminase (AST), alkaline phosphatase (ALP), and alanine transaminase (ALT). The results showed that there was a significant decrease in superoxide dismutase level (P<0.05). Changes in other markers (malondialdehyde and glutathione peroxidase) were however not statistically significant (P>0.05) when compared with the control. The extract significantly increased ALT, AST, ALP levels (p<0.05). Hence Breynia nivosa may be toxic and caution should be exercised in its consumption.

Comparative Study of Proximate and Phytochemical Analysis of the Roots of Justicia carnea Lindi. and Justicia secunda Vahl

Proximate and phytochemical analyses of the root extracts of Justicia carnea and Justicia secunda in the Acanthaceae family were investigated using standard procedures and compared. The result of the proximate analysis indicated that the roots of both species contain nutrients in varying levels. Protein (11.38±0.01), lipid (4.81±0.01) and moisture content (17.01±0.01) were higher in the roots of J. carnea than in J. secunda (8.32±0.01, 2.01±0.01, 11.22±0.02) respectively, while Carbohydrate (6.62±0.00), Ash (16.75±0.05) and Fibre (55.18±0.01) were higher in J. secunda than in J. carnea (4.73±0.02, 9.81±0.01, and 52.29±0.00) respectively. Qualitative phytochemical analysis showed the presence of tannin, flavonoid, alkaloids, saponin, phytate and cyanogenic glycosides whereas the result for the quantitative analysis showed that the quantity of phytochemicals in Justicia carnea and Justicia secunda were: tannin (46.75±0.00 and 41.01±0.01), flavonoid (2.72±0.01 and 3.21±0.00), alkaloid (10.16±0.00 and 11.21±0.01), saponin (3.31±0.01 and 2.7±0.00), phytate (30.54±0.01 and 33.86±0.00) and cyanogenic glycoside (100.01±0.00 and 500±0.00) respectively. Justicia carnea contained higher quantity of tannin and saponin while Justicia secunda contained higher amount of flavonoid, alkanoid, phytate and cyanogenic glycoside. These results conceivably indicated that the two species are good sources of essential nutrients which could be used in diets to supplement the daily nutrient needs in humans and animals, and phyto-nutrients which possess strong pharmacological activities, providing scientific credence for its therapeutic usage in folklore medicine.