POTENTIAL OF QUINOA FOR PRODUCTION OF NEW NON-DAIRY BEVERAGES WITH REDUCED GLYCEMIC INDEX

the production of non-dairy plant-based beverages was investigated. Developed products were analyzed for nutritional composition, sugars, glycemic index, technological parameters, and sensory acceptance in comparison with a commercial quinoa beverage. Quinoa beverages contained 0.60-0.63 g per 100 mL proteins, had a medium glycemic index and their energy values ranged from 113.14 to 120.79 kJ per 100 mL of beverage. For improvement sensory acceptance of beverages, these were sweetened with natural sweeteners with a low glycemic index (inulin or agave syrup). It was found that the final products had similar consistency as commercial quinoa drink, but showed a lower overall acceptance. Moreover, it was determined that the acceptance of beverages sweetened with agave syrup was higher than those sweetened with inulin. Due to the absence of gluten in quinoa and medium glycemic index of final products, the developed beverages can represent a new alternative for consumers with special nutritional needs. The addition of suitable ingredients may be recommended to improve their acceptance.


INTRODUCTION
In the last decades, considerable attention of researchers was oriented to inclusion of underutilised grains and pseudocereals (starch-rich grains, but dicotyledons) to different types of foods and beverages (Vega-Gálvez et al., 2010; Kaur and Tanwar, 2016; Urquizo et al., 2017;Lorruso et al., 2018).Quinoa (Chenopodium quinoa) is an ancient crop originated in the Andean region of South America that is known for its nutritional and health benefits (Zannini et al., 2018).Quinoa is a rich source of protein (12-20%), as its protein level is remarkably higher than in common cereals (Väkeväinen et al., 2020).The globulins (37%) and albumins (35%) are the major proteins found in quinoa, while prolamins are present in a low percentage (0.5-7.0%) (Dakhili et al., 2019).Due to this fact, the consumption of quinoa and quinoa derived products is recommended for celiac disease patients (Agregán et al., 2022).Moreover, the proteins of this pseudocereal contain a high amount of essential amino acids, such as lysine (5.1-6.4%)(limiting amino acid in some grains and wheat), methionine, and threonine (Urquizo et al., 2017; Aguilar et al., 2019;Sezgin and Sanlier, 2019).According to FAO/WHO recommendations, quinoa protein can supply over 180% of the daily recommended intake of essential amino acids for adult nutrition (Graf et al., 2015).Quinoa seeds also contain significantly higher amounts of minerals (calcium, magnesium, iron, and zinc) and some vitamins (E, B group, and C) than common cereals (Aguilar et al., 2018;Zannini et al., 2018).The main carbohydrate present in quinoa is starch (52-60%).Content of total dietary fibre in quinoa varied from 2.6 to 10% with about 78% of its fibre content being insoluble and 22% soluble The aim of this study was to assess the potential of underutilised pseudocereal quinoa for the production of gluten free beverages.The nutritional composition, physicochemical properties, and sensory acceptance of beverages were also determined.

Quinoa pretreatment
Before using quinoa seeds for beverages preparation, they were treated by desaponification, drying (at 60°C for 8 hours) and grinding according to the procedure that was previously reported by Urquizo et al. (2017).

Preparation of beverages
The procedure was adopted from Pineli et al. (2015) with several modifications.Pretreated seeds were mixed with water (12.5% quinoa in the mixture).The mixture was cooked for 30 minutes (gelatinization of starch) and cooled to 80°C.Subsequently, heat-stable bacterial alpha amylase (Termamyl SC DC, Novozymes) was added (calculated to 2 mL/kg of starch) and the mixture was heated at 80-85°C for 60 min, after that the enzyme was inactivated by boiling (15 min).The product was cooled to 40°C and filtered through gauze and then sunflower oil (0.8%, v/v) and lecithin (0.03%, w/v) were added.In the next step, four types of beverages (A-D) were formulated by adding the following ingredients in different combinations: xanthan gum (0.5%, w/v), inulin (3%, w/v), agave syrup (3%, v/v).The ingredients included in the individual beverages are presented in Table 1.Beverages were stored at 5°C.

Colour of beverages
The colour measurements were realised by Spectrophotometer Cary 300 (UV-VIS Agilent Technologies, Santa Clara, USA).Colour values were determined using the CIELAB colour system with reference to the illuminant D65 and a visual angle of 10°.The colour of the beverages was characterised as the whiteness index (WI) and was calculated according to the equation reported by Milovanovic et al. (2020).

Technological properties of beverages
Water holding capacity (WHC) of beverages was measured according to centrifugation method described by

Sensory evaluation of beverages
Sensory attributes of beverages were evaluated by panel assessors (11 -member panel) using a 9 -points hedonic scale (1 -dislike extremely; 9 -like extremely) (Walsh et al., 2014).Assessors evaluated taste, odour, colour, and consistency of prepared products.The overall acceptance of beverages was assessed by using 100 mm graphical unstructured line segments with specified end-points (Karovičová et al., 2020).The commercially available quinoa drink in the local Slovak market was used as a reference beverage (unflavored drink, Organic La Famiglia organic, Italy) (composed of spring water, organic quinoa, rice, sunflower oil, safflower oil, and sea salt).

Statistical analysis
All experimental analyses were carried out using three independent determinations and expressed as the mean value ± standard deviation.Statistical analyses were performed using Microsoft Excel (Microsoft Corp., Redmond, WA, USA) with XLSTAT for MS Excel Addinsoft SARL, Paris, France).A Pearson correlation analysis was applied to find the relationship between nutritional composition and glycemic properties of beverages.Analysis of variance was used to describe the significance differences (p<0.05) between the nutritional composition, technological properties, and sensory attributes of commercially produced and developed quinoa beverages.documented that the addition of sunflower oil to these types of beverages can improve the silky appearance of the final products.Due to these recommendations, sunflower oil was added to prepared beverages.Another ingredient added to the products was lecithin.This substance was applied as an emulsifying agent and also to improve the physical stability of beverages as was previously described by

Composition of beverages and their glycemic index
Nutritional composition of quinoa-based beverages is presented in Table 2.
Beverages prepared in this study contained 0.60-0.63g per 100 mL of proteins.2016).On the other hand, a significantly higher fat content was determined in the commercial quinoa drink (1.52 g per 100 mL).This could be related to the fact that the commercial product contained additional ingredients such as sunflower and safflower oil.Furthermore, it was observed that the developed beverages contained significantly lower amounts of total carbohydrates than the commercial drink, which was also reflected by lower energy value of the products.Sugar composition and GI of studied beverages are presented in Table 3. Prepared beverages were sweetened with sweeteners (inulin or agave syrup) that contributed to their sugar content in the products.52).These authors documented that a higher amount of proteins may have contributed, in part, to its lower GI.On the contrary, Shkembi and Huppertz (2023) described that the higher GI of plant derived drink may be due to the presence of starch, which leads to the release of glucose during digestion.
A Pearson correlation analysis was applied to find the relationship between the nutritional composition and glycemic properties of studied beverages.Strong negative correlations were observed between GI and content of glucose (r= -0.982) and fructose (r=-0.997).On the other hand, high positive correlations were found between GI and the starch and ash content (r=0.867 and r=0.877).Wills et al.
(1998) documented that monosaccharides, glucose and fructose, and total minerals are considered as nutrients with the strongest correlations with GI, this fact was also confirmed in this study.Moreover, strong correlations were found between energy value and protein (r=-0.962)and total carbohydrates (r=0.852) and between starch and glucose content (r=0.922).

Sensory evaluation of beverages
The sensory evaluation results of beverages are summarised in Table 6.From the sensory assessment, concluded that no significant differences were found in the consistency of evaluated commercial beverage and beverages included xanthan gum (beverages A and B).Moreover, it was found that beverages sweetened by agave syrup had about 14.1-16.3%higher taste score compared to beverages sweetened by inulin.This could be due to the fact, that inulin has a slight sweet taste and has only 10% sweetness in comparison with 100% for sucrose

CONCLUSION
The potential of underutilised crop quinoa as a raw material for production of nondairy beverages was presented in this study.It was concluded that pretreatment of seeds by desaponification removed saponins, bitter substances, which could decrease the acceptance of quinoa like products and application of thermostable alpha amylase during the processing effectively reduced starch content in the beverages.
Developed beverages contained 0.60-0.63g per 100 mL protein and had a medium GI.Moreover, it was found that all the developed beverages showed good stability without the serum separation during storage, and beverages that contained xanthan gum had higher viscosity and WHC than other beverages.Sensory evaluation showed that no significant differences were found in consistency of beverages containing xanthan gum and the control sample (commercial quinoa drink available in the Slovak markets).On the other hand, developed beverages had lower overall acceptance than control sample despite the fact that they were sweetened with low GI natural sweeteners.It was also determined that agave syrup was more acceptable as a sweetener due to its higher sweetness compared to inulin.
In conclusion, quinoa is a nutritionally rich raw material with absence of gluten and low GI that could be useful for the production of new or reformulated beverages for a group of consumers with specific nutritional needs.However, more research is needed not only to increase sensory acceptance of these products by consumers, but also to determine their nutritional profile and glycemic properties.

(
Bastidas et al., 2016; Navruz-Varli and Sanlier, 2016; Montemurro et al., 2019).Moreover, this crop contains about 3% of sugars, represented by high levels of D-xylose and maltose, a low amount of glucose and fructose (Graf et al., 2015; Gordillo-Bastidas et al., 2016; Navruz-Varli and Sanlier, 2016; Ahmed et al., 2019).The lipid content of quinoa ranges from 2 to 9.5%, which is a higher amount, as determined in maize (3-4%).The most abundant fatty acids are polyunsaturated fatty acids such as linoleic and alphalinolenic acids (Bastidas et al., 2016; Navruz-Varli and Sanlier, 2016; Montemurro et al., 2019).Quinoa is also an excellent source of phytosterols, lipophilic compounds with hypocholesterolemic effects, among which β-sitosterol is present in the highest amount (Navruz-Varli and Sanlier, 2016; Montemurro et al., 2019).Quinoa is also considered as a food with a low glycemic index (35-53, depending on the processing) (Vega-Galvez et al., 2010; Srujana et al., 2017) with slow glucose release into the bloodstream after intake (Lopes et al., 2019).Erfidan et al. (2022) described, that the consumption of quinoa is supposed to be beneficial in diabetes and associated hypertension.It was shown that intake of this pseudocereal significantly lowers blood sugar and increase the glucose tolerance in diabetic patients (Gabrial et al., 2016).Graf et al. (2015) demonstrated that 20hydroxyecdysone, the most abundant quinoa phytoecdysteroid, is responsible for the antidiabetic effect of these crops.In recent years, interest in plant-based beverages derived from different crops has been increasing worldwide (Jeske et al., 2017; Fernandes et al., 2018; Fructuoso et al., 2021; Pointke et al., 2022).On the other hand, only limited studies related to quinoa-based drinks are available (Pineli et al., 2015; Kaur and Tanwar, 2016; Urquizo et al., 2017; Sruthy et al., 2021).Due to the nutritional facts mentioned above, quinoa can have a great potential for production beverages with added value.
Aydar et al. (2020).Beverages A and B were also incorporated with xanthan gum.This ingredient has been reported as successful hydrocolloid for textural stabilisation of beverages (Kaur and Tanwar, 2016).Finally, the beverages were sweetened by inulin (beverages A and C) or agave syrup (beverages B and D).In recent years, these substances have become popular as natural substitutes for common sweeteners (such as sucrose or honey) with low GI (5-14 and 10-27, respectively) (Ozuna and Franco-Robles, 2022;Mudannayake et al., 2022;Saraiva et al., 2022).Besides that, inulin belongs to the class of dietary fibre known as fructan and is often applied in processed foods for its nutritional and therapeutic benefits (Ahmed and Rashid, 2019;Rungraeng et al., 2022).The concentration of added inulin was selected according to nutritional and health claims made on foods defined as a source of fibre(Kuchtová et al., 2018).

Table 1
Additional ingredients incorporated to beverages

Debrah et al., 2005; Pineli et al., 2015; Silva et al., 2020).
Due to this fact, alpha amylase was added to the mixture to liquefaction of gelatinized starch.Content of starch before the application of this enzyme in the studied mixture represented 5.75 ± 0.23 g per 100 mL, due to starch hydrolysis, the starch content in the final beverages was significantly reduced (11.13-11.82times lower content than in the original mixture).Previously, it was stated that higher GI of some plant-based beverages may be due to the presence of starch, which leads to the release of glucose during digestion (

Shkembi and Huppertz, 2023)
. Different ingredients can be added to plant-based beverages to improve their nutritional value, functional or sensory attributes (Mc Clements et al., 2019; Aydar et al., 2020; Fructuoso et al., 2021).According to Fructuoso et al. (2021), the addition of vegetable oils to plant-based beverages can provide a smooth mouthfeel similar to that of cow's milk.Aydar et al. (2020) and Pineli et al. (2015)

Tangyu et al. (2019) documented
that most commercial plant-based drinks contain little or even no protein (< 0.50 g per 100 mL).Values obtained from this study were higher than was previously determined by Jeske

Jeske et al., 2017).
Moreover, it was found that the commercial drink contained significantly higher amounts of glucose and maltose than experimentally prepared samples.The higher content of these components in the commercial product could be originated from the used ingredients (quinoa and rice).Previously, it was documented that plant drinks prepared from the ingredients which are rich source of starch, contains higher amount of maltose and glucose ( (Saraiva et al., 2022)rages B and D sweetened with agave syrup contained a significantly higher amount of fructose compared to other beverages.Fructose represents a sugar that is present in a high content (approximately 80%) in agave syrup(Saraiva et al., 2022).Content of maltose in developed beverages varied between 1.35 and 1.45 g per 100 mL.During beverage processing, alpha amylase was applied to the starch liquefaction.These enzymes catalyse starch hydrolysis to dextrins, oligosaccharides, maltose, and glucose (Presečki et al., 2013) and thus products of starch hydrolysis can represent another source of sugar in the beverages (Jeske et al., 2017).Previously, Pineli et al. (2015) prepared experimental unsweetened quinoa drink with increased content of proteins and low GI (

Table 2
Nutritional composition of quinoa-based beverages * denotes a statistically significant difference (p<0.05)

Table 3
Sugars compositions and glycaemic index of quinoa-based beverages

Clydesdale, 1991; Jeske et al., 2017).
Colour of samples was characterised as WI (Table4).This parameter indicates the degree of whiteness and mathematically combines lightness and yellow-blue into a single term (

Milovanovic et al., 2020; Al-Hilphy et al., 2022). WI
of developed beverages A and C were similar to commercial drink and quinoa drink that was previously reported by

Jeske et al. (2017).
The results also concluded that samples sweetened with inulin and agave syrup had significantly different WI, whereas beverages contained inulin were characterised by about 11.3-12.4% higher WI values.It could be probably due to the fact, that inulin is white in colour and has high WI and the colour of agave syrup can range from light amber to dark amber depending on the processing steps applied during its manufacture (

Willems and Low, 2012; Ahmed and Rashid, 2019)
(WI of applied sweeteners are shown in the Table4).

Table 4
Whiteness index of raw materials, quinoa-based beverages and commercial drinks

Technological properties of beverages
Technological properties of quinoa beverages are shown in the Table5.Viscosity is an essential quality parameter for obtaining food products with desirable attributes (

Zhao et al., 2003).
It was determined that beverages including xanthan gum were characterised by higher viscosity than other beverages.It was already documented that, xanthan gum increases the viscosity of beverages and also supports textural stability by reducing serum separation (

Table 5
Technological properties of quinoa-based beverages

Pineli et al., 2015; Karimidastjerd and Konuskan, 2018).
Overall acceptance of quinoa beverages is presented in Table6.The acceptance trend was as follows: beverage A < beverage C < beverage B < beverage D < commercially produced beverage.Previously, it was documented that quinoabased beverages are characterized with low sensory acceptance (This fact was also confirmed in this study.Several researchers indicated that flavoring the quinoa drinks or roasting of quinoa seeds before the processing could be a useful strategy to improve their acceptance by consumers (

Table 6
Sensory parameters of quinoa-based beverages and commercially produced quinoa drink * denotes a statistically significant difference (p<0.05)