Potato juice vs. traditional potato use - a new insight (review)

Traditionally, potatoes are consumed in a heat-treated form, e.g., boiled, fried, baked, with a significant part of its beneficial properties lost (A.D. Fabbri et al., 2015; J. Tian et al., 2016). Such processing greatly changes the mineral and vitamin composition of the product, the content of dietary fibre and the activity of secondary metabolites (J. Tian et al., 2016; A.T. Popova, 2019). Freshly squeezed potato juice can be a healthy alternative to heat-treated potatoes. Its use in folk medicine has been known since the early XIX century (J.E. Vlachojannis et al., 2010), while only a few scientific studies describe the physiological effects of potato juice consumption on experimental animals and on humans. One of the unique components of potato juice is resistant starch (L. Copeland et al., 2009). Resistant starch is not digested in the human body (P.J. Butterworth et al., 2011), positively affects the intestinal microbiota (I. Martínez et al., 2010), and normalizes insulin and glucagon-like peptide-1 in blood serum (A.A. Rashed et al., 2022). Of all plant proteins known to date, potato protein is the most balanced in essential amino acids and bioavailable to humans (M. Hussain et al., 2021). Its protease inhibitors are able to regulate digestion and have therapeutic effects in obesity (S. Komarnytsky et al., 2011; S. Nakajima et al, 2011), patatin has hypolipidemic (J. Wu et al., 2021), hypotensive (Y. Fu et al., 2019), antioxidant and antiproliferative properties (Y. Sun et al., 2013). Raw potatoes and their juice contain high concentrations of ascorbic acid (K.A. Beals et al., 2019), B vitamins, potassium, phosphorus, calcium, magnesium, iron and zinc (K. Zaheer et al., 2016; G.I. Piskun, 2023) which are essential for good health. Potato varieties with purple-, red- and yellow-coloured tubers are the richest source of polyphenols, primarily phenolic acids and anthocyanins (E.P. Shanina, 2013; H. Akyol et al., 2016; I.V. Kim et al., 2020). The potato glycoalkaloids solanine and chaconine remain the most controversial in terms of possible health benefits. On the one hand, their average content in potato tubers is low to cause symptoms of poisoning in humans (K. Nishie et al, 1971). On the other hand, experiments with pure extracts of glycoalkaloids proved their anticholinergic, anticholinesterase (V.A. Voronov et al., 2023) and cytotoxic effects o (M. Friedman, 2015; D.K. Zhao et al., 2021; M.L. Lanteri et al., 2023). In the review, we discuss the likely danger of the identified effects for human health vs. the prospects for the immunodeficiency correction, as well as prevention and treatment of cancer diseases (D.K. Zhao et al., 2021; M.L. Lanteri et al., 2023). We also focus on current methods of biodegradation of potato glycoalkaloids (R.C. Hennessy et al., 2020). Selected studies on the biological effects of potato peel extract (N. Singh et al., 2008) and potato juice (R. Muceniece et al., 2008; V. Bartova et al., 2018) are described. The above information shows that potato juice contains all the useful substances of intact raw potatoes. The prospects for using potato juice in functional nutrition are obvious, but it remains to determine the optimal technological methods for its mass production while preserving the biological activity of the components.