Evaluation of Sacha Inchi (Plukenetia volubilis L.) By-Products as Valuable and Sustainable Sources of Health Benefits

Abstract

By-products from sacha inchi (Plukenetia volubilis L.) oil extraction as the husk and shell are used as low value fertilizer or animal feed. The nutritive values, antioxidant activities, phenolics, and in vitro health-related activities of the sacha inchi husk and shell were investigated and compared to increase their economic potential as future food sources. Higher protein, carbohydrates, and total dietary fiber content were detected in the husk, while higher fat content and energy were found in the shell. Several phenolics were also detected in both the husk and shell, with p-coumaric acid being the most abundant phenolic in the shell and caffeic acid in the husk. Total phenolic content was 1.6-fold greater in the shell than in the husk, leading to 1.8–2.7-fold higher antioxidant activity and 1.2-fold higher anti-glycation activity. Various types and quantities of phenolics also led to diverse in vitro enzyme inhibitory activities in the husk and shell. Knowledge received from this research might be useful to maximize the utilization of by-products from sacha inchi oil extraction as future food sources with valuable nutritional compositions, phenolics, and potential health benefits. Further investigations on the health properties of the sacha inchi husk and shell should include toxicity, bioaccessibility, and in vivo experiments.

Effects of Maturity and Thermal Treatment on Phenolic Profiles and In Vitro Health-Related Properties of Sacha Inchi Leaves

“…Moreover, it has been demonstrated in the literature that the freeze-drying process could effectively preserve phenolics in plants, while TPCs in plant products obtained from freeze-drying process were close to those of the fresh materials [ 17 ]. TPCs in our freeze-dried leaf samples were comparable to those in fresh leaves of sacha inchi (~21 mg GAE/g DW) [ 12 ], and also far greater than previously reported TPCs in other parts of the plant [ 2 , 8 ]. These findings suggested that the freeze-drying technique could be adopted for retaining phenolic compounds with bioactivities from fresh sacha inchi leaves for further use.…”

“…In this study, eleven phenolics in young and mature sacha inchi leaves that underwent drying were identified by HPLC analysis as kaempferol, apigenin, isorhamnetin, gallic acid, 4-hydroxybenzoic acid, caffeic acid, vanillic acid, syringic acid, ferulic acid, p -coumaric acid and sinapic acid. All these phenolics, except apigenin, were previously observed in shells and husks discarded during the production of sacha inchi oil [ 8 ]. Our results revealed that both leaf maturation and drying processes had a profound effect on the amounts of individual phenolics detected in sacha inchi leaves.…”

“…The highest TPC value obtained from freeze-dried mature sacha inchi leaves (~21 mg GAE/g DW) was low compared to leaves with notably high TPCs such as peppermint and tea leaves (approximately 94–202 [ 21 ] and 77–178 [ 17 ] mg GAE/g DW, respectively). Higher levels of phenolics released from plant cells were achieved by optimizing the extraction parameters, particularly solvent, temperature and time [ 8 ]. Research suggested that an increase in maturity resulted in higher TPC in sacha inchi leaves, as demonstrated by Mokhtar et al (2021) [ 19 ].…”

“…Seed oil is known to contain several phytochemicals, e.g., tocopherols, phytosterols, carotenoids and polyphenols [ 2 , 3 , 6 ]. Husks and shells are nutrient-rich, especially the fiber and composed of health-promoting phenolics [ 8 ]. These sacha inchi parts have been previously reported to possess suppressive effects on some non-communicable diseases (NCDs) such as glycation reaction, hyperpigmentation and oxidative stress-related disorders [ 1 , 5 , 8 , 9 ].…”

“…Husks and shells are nutrient-rich, especially the fiber and composed of health-promoting phenolics [ 8 ]. These sacha inchi parts have been previously reported to possess suppressive effects on some non-communicable diseases (NCDs) such as glycation reaction, hyperpigmentation and oxidative stress-related disorders [ 1 , 5 , 8 , 9 ]. Extensive research has been conducted on different plant parts of sacha inchi but few studies have focused on the leaves.…”