Yacon (Smallanthus sonchifolius Poepp. & Endl) - the potential of a neglected crop as an alternative sweetener and source of phytochemicals for functional foods

Yacon (Smallanthus sonchifolius Poepp. & Endl.) as an underutilized crop, native to the Andean region, has attracted growing attention. The tuberous roots of yacon have been advertised as an alternative low caloric plant source for replacing sucrose. In fact, yacon has gained recognition based on the fact that its sweet tasting tuberous roots and its leaves have a favourable phytochemical content to be included in a range of functional food products. The leaves on the one hand are a significant source of health promoting phenolic compounds and their extract exerts certain biological activities such as antioxidant activity and hyperglycemic effects. The tubers on the other hand consist of carbohydrates including simple sugars, namely, fructose, glucose, sucrose and fructooligosaccharides (FOS). The FOS - representing the dominant polysaccharide in the tubers - are sweet tasting, prebiotic, and non-digestible oligosaccharides. Therefore, their consumption imposes several health benefits such as lowering the energy intake while enhancing the beneficial microflora of the colon. It is noted that 60-70 % of the dry matter content of yacon tubers is composed of FOS. Besides, yacon tubers are a remarkable source of biological components such as phenolic compounds. Thus, yacon is considered as multifunctional plant food. The main objectives of this thesis were to 1) differentiate between the quality of young and old yacon leaves of two cultivars (red and white) in terms of their total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity when using ohmic-assisted decoction (OH-DE) and decoction (DE) as well as energy consumption of extraction process, 2) differentiate between various parts of yacon tubers (flesh, peel and whole tuber) of seven cultivars in terms of their simple sugar (fructose, glucose and sucrose) content, TPC, TFC and antioxidant activity, 3) examine the TPC and antioxidant activity of yacon tubers of two cultivars (red and white) one week and three weeks after the harvest and under the influence of different pre-treatments before drying, and 4) determine the effect of drying on quality of yacon chips produced from two cultivars (red and white) at two time intervals after harvest. Overall, this thesis provided a broad dataset und information with regard to phytochemical contents of yacon leaves and tubers of different cultivars grown under the environmental conditions of southwestern Germany. However, further studies with regard to the determination of individual functional constitutes of leaves and tubers of yacon, their mechanism of action and effectiveness in promoting the health benefits, and their safety is essential. Moreover, with regard to novel product development from yacon leaves and tubers, further studies are strongly suggested to ensure the sustainability of final food products by optimizing energy consumption and environmental impacts of the whole food supply chain for such products as well as their quality.Yacon (Smallanthus sonchifolius Poepp. & Endl.), eine Knollenfrucht, die in der Andenregion heimisch ist, hat sich wachsende Aufmerksamkeit aufgezogen, da die Knollen als alternative, pflanzliche Zuckerquelle beworben wurden. Neben den Knollen stellen die Blätter eine bedeutende Quelle für gesundheitsfördernde phenolische Verbindungen dar und ihr Extrakt weist bestimmte biologische Aktivitäten, wie ein hohes antioxidatives Potenzial und hyperglykämische Wirkung, auf. Die Yaconknollen bestehen aus Kohlenhydraten einschließlich der Einfachzucker Fructose, Glucose,Saccharose und Fructooligosacchariden (FOS). Die FOS gelten als süß schmeckende, präbiotische Oligosaccharide. Ihr Verzehr führt zu einigen gesundheitlichen Vorteilen, wie der Verringerung der Energiezufuhr, während gleichzeitig die vorteilhafte Mikroflora des Dickdarms verbessert wird. Es wurde festgestellt, dass 60-70 % des Trockensubstanzgehalts der Yaconknolle aus FOS besteht. Außerdem sind Yaconknollen eine bemerkenswerte Quelle für biologische Komponenten wie etwa den phenolischen Verbindungen. Yacon gilt somit als multifunktionales pflanzliches Nahrungsmittel. Die Hauptzielen dieser Dissertation darin bestand: 1) die Qualität junger und alter Yaconblätter zweier Sorten (rot und weiß) hinsichtlich ihres Gesamtphenolgehaltes (TPC), des Gesamtflavonoidgehalts (TFC) und des antioxidativen Potenzials mit Hilfe der Verwendung verschiedener Extraktionsverfahren sowie dem Energieverbrauch des Extraktionsprozesses zu unterscheiden, 2) verschiedene Teile der Yaconknollen (Fruchtfleisch, Schale und ganze Knolle) hinsichtlich ihres Gehalts an Einfachzucker (Fructose, Glucose und Saccharose), TPC, TFC und der antioxidativen Aktivität zu unterscheiden, 3) die TPC- und Antioxidationsaktivität von zweier Sorten (rot und weiß) eine Woche und drei Wochen nach der Ernte und unter dem Einfluss verschiedener Vorbehandlungen vor der Trocknung zu untersuchen und, 4) die Auswirkung der Trocknung auf die Qualität von Yaconchips von zwei Sorten (rote und weiß) in zwei Zeitabständen nach der Ernte zu bestimmen. Insgesamtdie vorliegende Dissertation bietet eine umfassende Datengrundlage zu den phyotchemischen Gehalten verschiedener Inhaltsstoffe in Yaconblättern und knollen, die unter den gegebenen Umweltbedingungen in Südwestdeutschland erzeugt wurden. Um jedoch, sind weitere Studien zur Bestimmung der Zusammensetzung der Blätter und Knollen von Yacon, ihres Wirkmechanismus und ihrer Wirksamkeit im Hinblick auf ihre ernährungsphysiologischen Vorteile sowie die finale Produktsicherheit von wesentlicher Bedeutung. Im Hinblick auf die Entwicklung neuer Lebensmittelprodukte aus Yaconblättern und Knollen werden weitere Studien empfohlen, um die Nachhaltigkeit der Endprodukte zu gewährleisten und den Energieverbrauch und die Umweltauswirkungen der gesamten Wertschöpfungskette zu optimiere

Yacon (Smallanthus sonchifolius Poepp. & Endl) - the potential of a neglected crop as an alternative sweetener and source of phytochemicals for functional foods

Yacon (Smallanthus sonchifolius Poepp. & Endl.) as an underutilized crop, native to the Andean region, has attracted growing attention. The tuberous roots of yacon have been advertised as an alternative low caloric plant source for replacing sucrose. In fact, yacon has gained recognition based on the fact that its sweet tasting tuberous roots and its leaves have a favourable phytochemical content to be included in a range of functional food products. The leaves on the one hand are a significant source of health promoting phenolic compounds and their extract exerts certain biological activities such as antioxidant activity and hyperglycemic effects. The tubers on the other hand consist of carbohydrates including simple sugars, namely, fructose, glucose, sucrose and fructooligosaccharides (FOS). The FOS - representing the dominant polysaccharide in the tubers - are sweet tasting, prebiotic, and non-digestible oligosaccharides. Therefore, their consumption imposes several health benefits such as lowering the energy intake while enhancing the beneficial microflora of the colon. It is noted that 60-70 % of the dry matter content of yacon tubers is composed of FOS. Besides, yacon tubers are a remarkable source of biological components such as phenolic compounds. Thus, yacon is considered as multifunctional plant food. The main objectives of this thesis were to 1) differentiate between the quality of young and old yacon leaves of two cultivars (red and white) in terms of their total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity when using ohmic-assisted decoction (OH-DE) and decoction (DE) as well as energy consumption of extraction process, 2) differentiate between various parts of yacon tubers (flesh, peel and whole tuber) of seven cultivars in terms of their simple sugar (fructose, glucose and sucrose) content, TPC, TFC and antioxidant activity, 3) examine the TPC and antioxidant activity of yacon tubers of two cultivars (red and white) one week and three weeks after the harvest and under the influence of different pre-treatments before drying, and 4) determine the effect of drying on quality of yacon chips produced from two cultivars (red and white) at two time intervals after harvest. Overall, this thesis provided a broad dataset und information with regard to phytochemical contents of yacon leaves and tubers of different cultivars grown under the environmental conditions of southwestern Germany. However, further studies with regard to the determination of individual functional constitutes of leaves and tubers of yacon, their mechanism of action and effectiveness in promoting the health benefits, and their safety is essential. Moreover, with regard to novel product development from yacon leaves and tubers, further studies are strongly suggested to ensure the sustainability of final food products by optimizing energy consumption and environmental impacts of the whole food supply chain for such products as well as their quality.Yacon (Smallanthus sonchifolius Poepp. & Endl.), eine Knollenfrucht, die in der Andenregion heimisch ist, hat sich wachsende Aufmerksamkeit aufgezogen, da die Knollen als alternative, pflanzliche Zuckerquelle beworben wurden. Neben den Knollen stellen die Blätter eine bedeutende Quelle für gesundheitsfördernde phenolische Verbindungen dar und ihr Extrakt weist bestimmte biologische Aktivitäten, wie ein hohes antioxidatives Potenzial und hyperglykämische Wirkung, auf. Die Yaconknollen bestehen aus Kohlenhydraten einschließlich der Einfachzucker Fructose, Glucose,Saccharose und Fructooligosacchariden (FOS). Die FOS gelten als süß schmeckende, präbiotische Oligosaccharide. Ihr Verzehr führt zu einigen gesundheitlichen Vorteilen, wie der Verringerung der Energiezufuhr, während gleichzeitig die vorteilhafte Mikroflora des Dickdarms verbessert wird. Es wurde festgestellt, dass 60-70 % des Trockensubstanzgehalts der Yaconknolle aus FOS besteht. Außerdem sind Yaconknollen eine bemerkenswerte Quelle für biologische Komponenten wie etwa den phenolischen Verbindungen. Yacon gilt somit als multifunktionales pflanzliches Nahrungsmittel. Die Hauptzielen dieser Dissertation darin bestand: 1) die Qualität junger und alter Yaconblätter zweier Sorten (rot und weiß) hinsichtlich ihres Gesamtphenolgehaltes (TPC), des Gesamtflavonoidgehalts (TFC) und des antioxidativen Potenzials mit Hilfe der Verwendung verschiedener Extraktionsverfahren sowie dem Energieverbrauch des Extraktionsprozesses zu unterscheiden, 2) verschiedene Teile der Yaconknollen (Fruchtfleisch, Schale und ganze Knolle) hinsichtlich ihres Gehalts an Einfachzucker (Fructose, Glucose und Saccharose), TPC, TFC und der antioxidativen Aktivität zu unterscheiden, 3) die TPC- und Antioxidationsaktivität von zweier Sorten (rot und weiß) eine Woche und drei Wochen nach der Ernte und unter dem Einfluss verschiedener Vorbehandlungen vor der Trocknung zu untersuchen und, 4) die Auswirkung der Trocknung auf die Qualität von Yaconchips von zwei Sorten (rote und weiß) in zwei Zeitabständen nach der Ernte zu bestimmen. Insgesamtdie vorliegende Dissertation bietet eine umfassende Datengrundlage zu den phyotchemischen Gehalten verschiedener Inhaltsstoffe in Yaconblättern und knollen, die unter den gegebenen Umweltbedingungen in Südwestdeutschland erzeugt wurden. Um jedoch, sind weitere Studien zur Bestimmung der Zusammensetzung der Blätter und Knollen von Yacon, ihres Wirkmechanismus und ihrer Wirksamkeit im Hinblick auf ihre ernährungsphysiologischen Vorteile sowie die finale Produktsicherheit von wesentlicher Bedeutung. Im Hinblick auf die Entwicklung neuer Lebensmittelprodukte aus Yaconblättern und Knollen werden weitere Studien empfohlen, um die Nachhaltigkeit der Endprodukte zu gewährleisten und den Energieverbrauch und die Umweltauswirkungen der gesamten Wertschöpfungskette zu optimiere

Quinoa (Chenopodium quinoa Willd.): An overview of the potentials of the Golden Grain and socio-economic and environmental aspects of its cultivation and marketization

Quinoa (Chenopodium quinoa Willd.) is native to the Andean region and has attracted a global growing interest due its unique nutritional value. The protein content of quinoa grains is higher than other cereals while it has better distribution of essential amino acids. It can be used as an alternative to milk proteins. Additionally, quinoa contains a high amount of essential fatty acids, minerals, vitamins, dietary fibers, and carbohydrates with beneficial hypoglycemic effects while being gluten-free. Furthermore, the quinoa plant is resistant to cold, salt, and drought, which leaves no doubt as to why it has been called the “golden grain”. On that account, production of quinoa and its products followed an increasing trend that gained attraction in 2013, as it was proclaimed to be the international year of quinoa. In this respect, this review provides an overview of the published results regarding the nutritional and biological properties of quinoa that have been cultivated in different parts of the world during the last two decades. This review sheds light on how traditional quinoa processing and products evolved and are being adopted into novel food processing and modern food products, as well as noting the potential of side stream processing of quinoa by-products in various industrial sectors. Furthermore, this review moves beyond the technological aspects of quinoa production by addressing the socio-economic and environmental challenges of its production, consumption, and marketizations to reflect a holistic view of promoting the production and consumption of quinoa.We acknowledge the EIT Food education program which provided the funds for an open access publication in the context of the winning prize for top students of the summer school “Food Tech Transitions: reconnecting agri-food, technology, and society” (project number 19162).info:eu-repo/semantics/publishedVersio

Total Phenolic Content and Antioxidant Activity of Yacon (Smallanthus Sonchifolius Poepp. and Endl.) Chips: Effect of Cultivar, Pre-Treatment and Drying

Recent studies have associated the consumption of yacon root as a functional plant food with reduced glycemic index and, due to its considerable phenolic acid levels, a protection of cell membranes against free radical damage. This study examined the effect of four different treatments including: (1) storage duration after harvest (one and three weeks after harvest); (2) pre-treatment before drying (untreated, pre-treatment with diluted lime juice); (3) drying method (freeze drying (FD) and convective hot air drying (CHAD)); and (4) cultivar (white and red), on the quality of yacon (Smallanthus sonchifolius Poepp. and Endl.) chips in terms of their total phenolic content (TPC) and antioxidant activity (AA) (ABTS (2,2′-Azino-Bis (3-Ethylbenzothiazoline-6-Sulfonic Acid) Diammonium Salt) radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and ferric reducing antioxidant power (FRAP)). Overall, the chips that were produced using pre-treatment with diluted lime juice and FD had the highest amounts of TPC and AA. Regarding the chips produced by means of CHAD, retention of higher TPC and AA was possible with lime-juice pre-treatment and use of higher hot air temperatures. Moreover, chips produced from the white cultivar had higher TPC and AA than chips produced from the red cultivar

Yacon (Smallanthus sonchifolius Poepp. & Endl.) as a Novel Source of Health Promoting Compounds: Antioxidant Activity, Phytochemicals and Sugar Content in Flesh, Peel, and Whole Tubers of Seven Cultivars

The aim of this study was to evaluate the quality characteristics of seven yacon (Smallanthus sonchifolius Poepp. and Endl.) cultivars (Cajamarca, Cusco, Early White, Late Red, Morado, New Zealand and Quinault) cultivated in the southwest of Germany. The following phyto/chemical traits were investigated in different yacon tuber parts (flesh, peel, and whole tubers): total dry matter, sugar content (fructose, glucose, and sucrose content), total phenolic content (TPC), total flavonoid content (TFC), 2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and Ferric reducing antioxidant power (FRAP). The results indicated a significant interaction between cultivar and tuber part on all of the examined traits (p < 0.0001). Of flesh and whole tuber, cv. Late Red, cv. Morado, and cv. Cajamarca had the highest TPC, TFC, DPPH radical scavenging activity, and FRAP. They also had relatively higher total sugar content. Cv. New Zealand had the lowest amount of sugars, TPC, TFC, DPPH radical scavenging activity, and FRAP, but the highest ABTS radical scavenging activity content in its flesh and whole tuber. Moreover, the results indicated that the peel of yacon tubers contained considerably high amounts of phytochemicals while possessing low sugar contents. Overall, this study provides a broad insight into the phyto/chemical content of yacon tubers from different cultivars, which can be used for further breeding programs, and the selection of proper cultivars for specific food product development

Impact of ohmic-assisted decoction on bioactive components extracted from yacon (Smallanthus sonchifolius Poepp.) leaves: comparison with conventional decoction

Yacon (Smallanthus sonchifolius Poepp.) leaves are a potentially rich source of bioactive compounds, such as phenolic acids and flavonoids. In this study, the effect of the extraction method (ohmic-assisted decoction (OH-DE) and decoction (DE)), yacon cultivar (red and white), and leaf age (young and old) on the quality/quantity of extracted phytochemicals were investigated. Extraction yield, energy consumption, total phenolic content (TPC), total flavonoid content (TFC), ABTS and DPPH radical scavenging activity, and ferric reducing antioxidant power (FRAP) were determined. Additionally, HPLC-DAD was used to identify the major individual phenolic and flavonoid compounds of yacon leaves. The results showed that a three-way interaction of process-variables (extraction methodxyacon cultivarxage of leaves) influenced the extraction yield, TPC, TFC, ABTS, and DPPH radical scavenging activity, and FRAP, significantly (p < 0.05). However, energy consumption of the extraction process was only affected by method of extraction (p < 0.05) and was halved when OH-DE was applied as compared to DE alone. Additionally, the phytochemical quality of extracts was either improved or comparable when OH-DE was used for extraction. Also, it was shown that yacon leaves contained considerable amounts of caffeic acid, chlorogenic acid, ferrulic acid, myricetin, p-coumaric acid, and rutin, while leaves of the red cultivar had higher contents of each compound compared to leaves of the white cultivar