Comparative Study on the Physico-Chemical, Textural and Thermal Properties of Instant Porridges Based on Spelt and Oats Introduc

Home , Breakfast cereal, Food, Gruel, Porridge

DOI: 10.5937/FFR1801027S UDK 641.56:633.11+633.13]:66.022.392 Original research paper

COMPARATIVE STUDY ON THE PHYSICO-CHEMICAL, TEXTURAL AND THERMAL PROPERTIES OF INSTANT PORRIDGES BASED ON SPELT AND OATS Olivera D. Šimurina*, Bojana V. Filipčev, Boško D. Marić, Biljana R. Cvetković, Marija I. Bodroža Solarov

University of Novi Sad, Institute of Food Technology, 21000 Novi Sad, Bulevar cara Lazara 1, Serbia

*Corresponding author: Phone: +381 21 485 3778 E-mail address: [email protected]

ABSTRACT: Changing of food habits and increased preference for healthy meals, along with the growth of breakfast industry has increased the size of “ready-made“ and instant porridge market in Serbia. Porridges dominantly marketed are those based on oats. However, there is a growing interest of local producers to use other cereals for porridge production. Therefore, this work was aimed to estimate the porridge-making ability of spelt wheat (Triticum aestivum spp. spelta) in comparison to that of oats. The studied porridges are instant products, based on extruded spelt or oat flour. The proximate composition, hydration properties (water absorption index-WAI and water solubility index- WSI), consistency and thermal properties were determined with the aim to compare the characteristics of the porridges. In general, the spelt-based porridge had more total and insoluble fibреs, proteins, minerals and less available carbohydrates in comparison to the oat porridge. The spelt porridge may be eligible to bear the nutritional claim „high-fibre“ which is advantageous for the market viability of the product. Both porridges had >20% of damaged starch due to high initial content in the flours and extrusion processing of flours, though spelt-based extrudate and porridge were significantly higher in this parameter. Oat-based extrudate and porridge were higher in resistant starch content. The consistency was similar between the porridges, although spelt tended to form slightly firmer and cohesive porridge. Spelt porridge had better hydration properties (higher WAI) which are a featured attribute for this kind of product, similarly to higher consistency values. Spelt wheat, in its extruded form, is a suitable ingredient for porridge production. Key words: porridge, spelt, oats, hydration, composition, consistency, gelatinization

INTRODUCTION

Porridge is a traditional and staple food in rations (Khan et al., 2014) and in the case many countries, especially developing of food emergency situations. Traditional ones. In modern cultures, porridge is en- porridges in developing countries are joying a revival as a healthy breakfast based on local staple cereals (wheat, rice, food. Porridge is a convenient food for millet, sorghum, maize) and starchy tubers weaning infants, elderly and convales- (cassava, potato and plantain). Cereal- cents due to easy digestibility (Rhim et al., based porridges are usually prepared by 2011). It is also very useful food for mi- cooking of cracked or previously soaked litary troops as it can be produced to be grains. In Northern Europe and North light in weight and long in shelf-life which America, porridge is usually made from makes it convenient for operational pack oats cooked in water and/or milk but it can

27 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 be prepared from maize, barley and rice the quality parameters of spelt and oat in- standard methods: moisture (No. 926.5), temperatures and enthalpy of gelatine- as well. Depending on the proportion of stant porridges, in order to evaluate the ash (No. 930.22), crude proteins (No. zation (H) were determined. Gelatiniza- the cereals and liquid, two types of por- feasibility of spelt wheat for this product 950.36), fat (No. 935.38), dietary fibres tion temperatures and enthalpy changes ridges prepared for consumption can be type. The instant porridges were based on (No. 958.29). Carbohydrates were ob- were calculated using Proteus Thermal distinguished: thick and thin porridges. extruded spelt and oat flour and were tained by calculation according to Analysis software (Netzsch, Germany). Thick porridges are solid-like and can be formulated to bear a „high-protein“ nutri- FAO/WHO guidelines using the equations Determination of textural properties eaten with spoon or hand whereas thin tional claim (min. 20% energy comes from 1 and 2 (FAO, 2003): porridge or gruel is consumed by drinking protein (Regulation (EC) No. 1924/2006)). Total carbohydrates (g/ 100 g) = 100-(protein+ A Texture Analyser (TA-XTplus, SMS, as having fluid or semi-fluid consistency fat + water + ash + alcohol) (1) Godalming, England) was used to mea- (Moussa et al., 2011). Thin porridge is MATERIALS AND METHODS sure the consistency and cohesiveness of Available carbohydrates (g/100 g) = 100- usually used as a complementary meal for Materials the samples according to the back-ex- infants. (protein+ fat + water + ash + alcohol + total trusion method. Measurements were per- Spelt and oat flours and extrudates were fibre) (2) Today, development of food processing formed in a beaker in which the samples kindly donated from local producer Damaged and resistant starch contents of were mixed with warm water as explained technologies enabled the production of „BioLutisа“d.o.o., Mošorin, Serbia. The „ready-made“ porridges which do not need the samples were determined according to above (paragraph Materials). A 35-mm whole grain flours were obtained by abra- procedures given in the Damaged Starch disc probe was used to penetrate the sam- long preparation and are convenient for sive milling on a stone grinder mill, after use. Oats for porridge are processed by and Resistant Starch Assay Kits (Mega- ples. All measurements were made in five thorough cleansing and dehulling of zyme International Ltd., Wicklow, Ireland). replications after cooling of the samples to (hydro) thermal treatments (kilning, stea- grains. The grinded material was sifted feeding temperatures (37 C). An indicator ming), sizing, cutting and flaking. Different and flour fraction between 180 and 350 Determination of hydration properties of firmness was an area under the curve forms of porridge oats can be distin- μm was used to produce extrudates. Ex- Water absorption index (WAI) and water registered during the penetration of the guished: pinhead (outer husk not re- trusion was performed on a single-screw solubility index (WSI) were the parameters probe into the sample. Cohesiveness was moved), rolled oat flakes (removed outer extruder under the following processing to describe the hydration properties of measured as a peak force registered upon husk, groats steamed, flattened and parameters: temperature 180 °C, time 150 porridges. WAI and WSI of the porridges the probe return and it is actually an rolled), steel-cut oats or Irish oats (re- s, pressure 150 bar, shear rate≥ 100 s-1, were determined as outlined in Yadav et indication of the sample’s resistance to moved outer husk, groats cut into 2-3 screw rotating speed 500 rpm and energy al. (2014) and Mandge et al. (2014). 3 g of flow off of the disc. The test settings were: pieces), Scottish oatmeal (groats stone- consumption 1.8 MJ/kg. After extrusion, sample was dispersed in 30 ml distilled test speed 1.0 mm/s, trigger force 10 g grinded instead of steel cut). Rolled oat extrudates were ground on a hammer mill. flakes can be regular, quick (thinner fla- water at room temperature and gently and travel distance 30 mm. High-protein dry instant porridges were stirred. After 30 min hydration, the dis- kes, more steamed) or instant (pre-co- Statistical analysis oked, rolled even thinner, dehydrated). finally prepared by blending the grinded persion was centrifuged at 3000 x g for 10 extruded spelt or oat with other ingredients min. Supernatant was carefully decanted Experimental data were statistically analy- Extrusion cooking is a processing techno- following the proportion in the formulation: into weighted evaporated dish and dried to sed by means of one-way ANOVA follo- logy widely used to produce „ready-to-eat“ extrudate (100 g), oat flakes (23.1 g), soy constant mass at 110 C. The remaining wed by Tukey’s (HSD) post-hoc test and breakfast cereals, expanded snacks and protein isolate (23.1 g), caseine (23.1 g), gel was weighed and WAI (g/g) was ex- considering significant values at p0.05 instant cereal-based foods. Extrusion of- and xylitol (23.1 g). The other ingredients pressed as the ratio of gel weight and dry (software Statistica 13, Tulsa, OK). fers many advantages to processors: high used in porridge formulation were pro- weight of sample. WSI (%) was expressed throughput, energy efficiency, thermal con- cured from local food stores and their ori- as the percentage of dried supernatant in RESULTS AND DISCUSSION trol, short processing time and ability to in- gin is as follows: oat flakes ‘‘Italico”, Bečej, dry weight of sample. corporate wide variety of ingredients to the Serbia; soy protein isolate ‘‘Yucheng Composition DSC measurements final product (Eastman et al., 2001). Ex- Crown Soya Protein Foods Co.” Ltd., Chi- Spelt flour had higher content of proteins, trusion is a convenient way to produce in- na; Na-caseinate Rovita FN 5 S ‘‘Rovita” DSC studies of oat/spelt flour, grinded ex- ash, total and insoluble fibres in com- stant cereal porridges which require mi- GmbH, Germany, xylitol ‘‘Danisco Cultor trudate and dry porridge blend samples parison to oat flour which was higher in fat nimum preparation time-simple, quick re- AG”, Switzerland. were performed on a differential scanning and soluble fibre content (Table 1). These constitution with warm or cold water or Reconstituted porridge was prepared by calorimeter DSC 204F1 Phoenix (Netzsch, relations remained similar after extrusion milk. pouring over the dry porridge blend with Germany). Approximately 3 mg of sample of the flours and in the formulated por- In recent times, porridge has become a warm water (50 C) at 1:2.5 (w/w) dry was weighed into an Al crucible. Distilled ridges. Higher ash content in spelt flour popular meal in Serbia. Prevalent por- blend : water ratio. After vigorous mixing, water was added with a microsyringe to and extrudates imply to higher content of ridges are those based on oats and they the porridge was given 10 min to rest and reach a water-to-dry solid ratio of 2.5:1 minerals. The damaged starch content are usually sold in retail markets in the swell. (w/w). The crucible was sealed with a lid was similarly high in both oat and spelt form of pre-made (sweetened and fla- and left to equilibrate overnight at room flour (around 25%), probably due to grin- Proximate analysis and damaged/resistant temperature. The equilibrated sample was ding on a stone mill. Interestingly, ex- voured) instant porridges. However, there starch content is an interest of local producers of organic then heated in the temperature range 30- trusion did not increase the damaged cereals to produce porridges from other Proximate composition of samples of raw 120 C with a heating rate 3 C/min. From starch content. In contrast, resistant starch cereals like spelt wheat. Therefore, in this flour, extrudates and dry porridge blends the receiving thermograms, the onset (T0), content increased after extrusion of oat work, a comparison was made between were analysed according to AOAC (2000) peak (Tp) and endset (Te) gelatinization flour but decreased in the case of spelt

28 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 be prepared from maize, barley and rice the quality parameters of spelt and oat in- standard methods: moisture (No. 926.5), temperatures and enthalpy of gelatine- as well. Depending on the proportion of stant porridges, in order to evaluate the ash (No. 930.22), crude proteins (No. zation (H) were determined. Gelatiniza- the cereals and liquid, two types of por- feasibility of spelt wheat for this product 950.36), fat (No. 935.38), dietary fibres tion temperatures and enthalpy changes ridges prepared for consumption can be type. The instant porridges were based on (No. 958.29). Carbohydrates were ob- were calculated using Proteus Thermal distinguished: thick and thin porridges. extruded spelt and oat flour and were tained by calculation according to Analysis software (Netzsch, Germany). Thick porridges are solid-like and can be formulated to bear a „high-protein“ nutri- FAO/WHO guidelines using the equations Determination of textural properties eaten with spoon or hand whereas thin tional claim (min. 20% energy comes from 1 and 2 (FAO, 2003): porridge or gruel is consumed by drinking protein (Regulation (EC) No. 1924/2006)). Total carbohydrates (g/ 100 g) = 100-(protein+ A Texture Analyser (TA-XTplus, SMS, as having fluid or semi-fluid consistency fat + water + ash + alcohol) (1) Godalming, England) was used to mea- (Moussa et al., 2011). Thin porridge is MATERIALS AND METHODS sure the consistency and cohesiveness of Available carbohydrates (g/100 g) = 100- usually used as a complementary meal for Materials the samples according to the back-ex- infants. (protein+ fat + water + ash + alcohol + total trusion method. Measurements were per- Spelt and oat flours and extrudates were fibre) (2) Today, development of food processing formed in a beaker in which the samples kindly donated from local producer Damaged and resistant starch contents of were mixed with warm water as explained technologies enabled the production of „BioLutisа“d.o.o., Mošorin, Serbia. The „ready-made“ porridges which do not need the samples were determined according to above (paragraph Materials). A 35-mm whole grain flours were obtained by abra- procedures given in the Damaged Starch disc probe was used to penetrate the sam- long preparation and are convenient for sive milling on a stone grinder mill, after use. Oats for porridge are processed by and Resistant Starch Assay Kits (Mega- ples. All measurements were made in five thorough cleansing and dehulling of zyme International Ltd., Wicklow, Ireland). replications after cooling of the samples to (hydro) thermal treatments (kilning, stea- grains. The grinded material was sifted feeding temperatures (37 C). An indicator ming), sizing, cutting and flaking. Different and flour fraction between 180 and 350 Determination of hydration properties of firmness was an area under the curve forms of porridge oats can be distin- μm was used to produce extrudates. Ex- Water absorption index (WAI) and water registered during the penetration of the guished: pinhead (outer husk not re- trusion was performed on a single-screw solubility index (WSI) were the parameters probe into the sample. Cohesiveness was moved), rolled oat flakes (removed outer extruder under the following processing to describe the hydration properties of measured as a peak force registered upon husk, groats steamed, flattened and parameters: temperature 180 °C, time 150 porridges. WAI and WSI of the porridges the probe return and it is actually an rolled), steel-cut oats or Irish oats (re- s, pressure 150 bar, shear rate≥ 100 s-1, were determined as outlined in Yadav et indication of the sample’s resistance to moved outer husk, groats cut into 2-3 screw rotating speed 500 rpm and energy al. (2014) and Mandge et al. (2014). 3 g of flow off of the disc. The test settings were: pieces), Scottish oatmeal (groats stone- consumption 1.8 MJ/kg. After extrusion, sample was dispersed in 30 ml distilled test speed 1.0 mm/s, trigger force 10 g grinded instead of steel cut). Rolled oat extrudates were ground on a hammer mill. flakes can be regular, quick (thinner fla- water at room temperature and gently and travel distance 30 mm. High-protein dry instant porridges were stirred. After 30 min hydration, the dis- kes, more steamed) or instant (pre-co- Statistical analysis oked, rolled even thinner, dehydrated). finally prepared by blending the grinded persion was centrifuged at 3000 x g for 10 extruded spelt or oat with other ingredients min. Supernatant was carefully decanted Experimental data were statistically analy- Extrusion cooking is a processing techno- following the proportion in the formulation: into weighted evaporated dish and dried to sed by means of one-way ANOVA follo- logy widely used to produce „ready-to-eat“ extrudate (100 g), oat flakes (23.1 g), soy constant mass at 110 C. The remaining wed by Tukey’s (HSD) post-hoc test and breakfast cereals, expanded snacks and protein isolate (23.1 g), caseine (23.1 g), gel was weighed and WAI (g/g) was ex- considering significant values at p0.05 instant cereal-based foods. Extrusion of- and xylitol (23.1 g). The other ingredients pressed as the ratio of gel weight and dry (software Statistica 13, Tulsa, OK). fers many advantages to processors: high used in porridge formulation were pro- weight of sample. WSI (%) was expressed throughput, energy efficiency, thermal con- cured from local food stores and their ori- as the percentage of dried supernatant in RESULTS AND DISCUSSION trol, short processing time and ability to in- gin is as follows: oat flakes ‘‘Italico”, Bečej, dry weight of sample. corporate wide variety of ingredients to the Serbia; soy protein isolate ‘‘Yucheng Composition DSC measurements final product (Eastman et al., 2001). Ex- Crown Soya Protein Foods Co.” Ltd., Chi- Spelt flour had higher content of proteins, trusion is a convenient way to produce in- na; Na-caseinate Rovita FN 5 S ‘‘Rovita” DSC studies of oat/spelt flour, grinded ex- ash, total and insoluble fibres in com- stant cereal porridges which require mi- GmbH, Germany, xylitol ‘‘Danisco Cultor trudate and dry porridge blend samples parison to oat flour which was higher in fat nimum preparation time-simple, quick re- AG”, Switzerland. were performed on a differential scanning and soluble fibre content (Table 1). These constitution with warm or cold water or Reconstituted porridge was prepared by calorimeter DSC 204F1 Phoenix (Netzsch, relations remained similar after extrusion milk. pouring over the dry porridge blend with Germany). Approximately 3 mg of sample of the flours and in the formulated por- In recent times, porridge has become a warm water (50 C) at 1:2.5 (w/w) dry was weighed into an Al crucible. Distilled ridges. Higher ash content in spelt flour popular meal in Serbia. Prevalent por- blend : water ratio. After vigorous mixing, water was added with a microsyringe to and extrudates imply to higher content of ridges are those based on oats and they the porridge was given 10 min to rest and reach a water-to-dry solid ratio of 2.5:1 minerals. The damaged starch content are usually sold in retail markets in the swell. (w/w). The crucible was sealed with a lid was similarly high in both oat and spelt form of pre-made (sweetened and fla- and left to equilibrate overnight at room flour (around 25%), probably due to grin- Proximate analysis and damaged/resistant temperature. The equilibrated sample was ding on a stone mill. Interestingly, ex- voured) instant porridges. However, there starch content is an interest of local producers of organic then heated in the temperature range 30- trusion did not increase the damaged cereals to produce porridges from other Proximate composition of samples of raw 120 C with a heating rate 3 C/min. From starch content. In contrast, resistant starch cereals like spelt wheat. Therefore, in this flour, extrudates and dry porridge blends the receiving thermograms, the onset (T0), content increased after extrusion of oat work, a comparison was made between were analysed according to AOAC (2000) peak (Tp) and endset (Te) gelatinization flour but decreased in the case of spelt

29 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 flour. The formation of resistant starch du- on the availability of hydrophilic groups to ween the oat and spelt wheat starches. gars and the rest of starch. Zhu et al. ring extrusion depends on the moisture bind water molecules and on the gel Oat starch granules are the smallest in (2016) reported discrepancies in estima- content and extrusion variables (Núňez et forming capacity of macromolecules comparison to other cereals, which also tion of starch gelatinization degree bet- al., 2009). Even minor changes of process (Mandge et al., 2014). WAI was observed affects the pasting properties (Zhou et al., ween DSC method and enzymatic me- parameters which affect starch gela- to increase with higher starch content 1998). The observed melting enthalpies thod, observing that DSC method tended tinization and retrogradation may induce (Gandhi and Singh, 2015). Gelatinized for oat and spelt (Tab. 3) are lower than to produce overestimated results. starch and starch damaged by extrusion- huge differences in the resistant starch those reported by other researchers Textural properties content in food (Perera et al., 2010). Spelt induced fragmentation increases WAI (Ra- (Núňez et al., 2009; Gałkowska et al., flour, extrudate and porridge contained yas-Duarte et al., 1988). WAI can also be 2014) but this might be due to the fact that Aqueous slurries of oat and spelt flours less available carbohydrates in compa- affected by protein macromolecules as ob- the results reported here are not ex- were flowable and showed little resistance rison to those of oats but slightly higher served by Mandge et al. (2014) who pressed in grams of starch. After ex- to back-extrusion force. The difference in content of damaged starch and less re- reported that instant multigrain porridge trusion, the endothermic peak disappeared consistency between spelt and oat por- sistant starch. The lower available carbo- increased WAI when processed at higher (Fig. 1) for both spelt and oat, suggesting ridge was not statistically significant hydrate content may be favourable in for- temperatures, causing denaturation of pro- that starch underwent complete gelatine- (p>0.05) although spelt porridge tended to mulating diets with lower dietary carbo- teins. WSI reflects on the degree of starch zation and that starch granules were fully form a firmer and more cohesive porridge hydrates but the presence of damaged degradation as it measures low molecular disrupted. This is in line with the DSC (Fig. 3). starch and less resistant starch may be weight molecules dissolved in the water thermographs of cereal and pseudocereal In contrast, the paste of extruded flours less favourable regarding glycaemic im- (Kirby et al., 1988). WSI can be a predictor flours after extrusion reported by Robin et showed remarkable increase in firmness pact. Resistant starch is not digested in of the susceptibility of food to digestion al. (2015). However, in oat and spelt ex- and cohesiveness due to increased water the human small intestine but is fermented which is important in designing weanening trudates, around 24% damaged (gelati- absorption capacity. Oat extrudates sho- in the large bowel providing numerous food for infants (Nguyen et al., 2010). nized) starch was measured by enzymatic wed an ability to form a cohesive mass. health-beneficial effects such as reduction Flours of spelt and oat showed similar WAI method (Tab. 1) which was in contrast to Higher firmness and viscosity is a desi- in the glycaemic response, cholesterol values (1.22 and 1.33 g/g, respectively) DSC data that suggested 100% gelatine- rable property in porridges (Yadav et al., reducing effect and anticarcinogenic effect whereas spelt flour had higher WSI zation. Since the content of available 2014) but quantitative guidelines on the in colon (Asp et al., 1992). On the other (7.09%) than the oat flour (3.73%). After carbohydrates is 65-69%, theoretically, the acceptable consistency of porridge does hand, damaged (gelatinized) starch is extrusion, WAI and WSI in oat and spelt remaining 40-45% could account for su- not exist (de Carvalho et al., 2014). more susceptible to digestion. Starch significantly increased. Earlier reports digestion and consequently, the metabolic suggest that WAI and WSI tend to response, depends on many factors increase after extrusion process (Ding et Table 1. Proximate composition, damaged and resistant starch contents of the oat and spelt flours, extrudates including starch gelatinization degree, pre- al., 2005; Jozinović et al., 2016). Jozinović a-e sence of indigestible polymers (dietary et al. (2016) related a post-extrusion and porridges ( Marks with different letters in the same row indicate statistical significance at p<0.05) fibres), proteins. etc. (Granfeldt et al., increase in WAI and WSI with starch Parameter Flour Extrudate Dry porridge blend 1992). To predict the real glycaemic im- damage in corn grits extrudates. Higher (% d.m.) Oat Spelt Oat Spelt Oat Spelt pact of spelt and oat porridges, it is WAI in porridges is affirmative for the Moisture 11.480.11d 11.670.10d 7.410.05a 9.960.08c 7.340.04a 8.370.04b required to study the digestible and in- production of thick porridges for people on a b b c c d Ash 1.830.07 2.290.09 2.160.08 2.620.13 2.620.11 3.310.10 digestible fractions of starch in more detail. weight-reducing diet because it would b c a d e f The porridge based on spelt may be provide adequate, thick consistency por- Proteins 13.590.04 15.870.06 12.870.03 18.010.05 29.390.08 32.390.03 e c f a d b labelled „high-fibre“ as it provides >6 g of ridge but with less calories per a portion. Fat 6.400.05 2.490.03 7.270.04 1.210.01 4.560.04 1.580.02 fibres per 100 g whereas oat porridge may The porridges had higher WSI in com- Total fibres 6.580.02b 10.160.05d 8.700.04c 12.870.05e 5.370.02a 8.890.03c bear the nutritional claim „source of fibre“ parison to the corresponding extrudates Insoluble fibres 4.350.01b 8.150.04e 5.480.03c 10.010.05f 3.430.02a 6.720.04d according to Nutritional Claims for food probably due to presence of other ingre- Soluble fibres 2.230.01b 2.010.012a 3.220.018d 2.860.02c 1.930.017a 2.170.01b (Regulation (EC) No. 1924/2006 lastly dients in their formulation. Total carbohydrates d e c d b a 78.180.27 79.350.28 77.700.20 78.160.27 63.430.27 62.7219 amended by Regulation (EU) No by calculation 1047/2012). Oat is rich in beneficial so- Thermal analysis Available carbohyd. e d d c b a 71.610.29 69.190.33 69.000.24 65.300.32 58.060.29 53.840.22 luble fibre, beta-glucan, which also sub- DSC results for the spelt/oat flours and ex- by calculation  e  e  c  d  a  b jects to labelling and is additionally advan- trudates are displayed in Tab. 3 and Fig. Damaged starch 25.52 0.25 25.84 0.22 24.10 0.20 24.72 0.19 20.78 0.21 22.43 0.18 e b f a d c tageous feature to increase the market 1. Oat and spelt flours showed a charac- Resistant starch 1.910.03 0.830.02 2.310.03 0.740.02 1.820.03 1.160.02 viability (Regulations (EU) No. 432/2012). teristic gelatinization peak (Fig. 1) which results from the gelatinization of the starch Table 2. Hydration properties a-b granules in excess water, caused by the Gelatinization temperature and enthalpy of the oat and spelt flours. ( Marks with different letters in WAI indicates the hydration properties of melting of crystalline structure of starch. the same column indicate statistical significance at p<0.05) To Tp Te H materials in excess water and is generally Oat flour showed lower onset, peak and Sample (°C) (°C) (°C) attributed to the ability of starch to absorb endset temperatures in comparison to the (J/g d.m.) Oat flour  a  a  a  a water or, indirectly, the proportion of intact spelt flour which is attributable to differen- 55.4 0.3 62.0 0.2 67.6 0.1 6.4 0.5 b b b b and gelatinized starch. Actually, it depends ces in the structure and crystallinity bet- Spelt flour 61.70.2 65.10.1 69.20.2 5.20.4

30 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 flour. The formation of resistant starch du- on the availability of hydrophilic groups to ween the oat and spelt wheat starches. gars and the rest of starch. Zhu et al. ring extrusion depends on the moisture bind water molecules and on the gel Oat starch granules are the smallest in (2016) reported discrepancies in estima- content and extrusion variables (Núňez et forming capacity of macromolecules comparison to other cereals, which also tion of starch gelatinization degree bet- al., 2009). Even minor changes of process (Mandge et al., 2014). WAI was observed affects the pasting properties (Zhou et al., ween DSC method and enzymatic me- parameters which affect starch gela- to increase with higher starch content 1998). The observed melting enthalpies thod, observing that DSC method tended tinization and retrogradation may induce (Gandhi and Singh, 2015). Gelatinized for oat and spelt (Tab. 3) are lower than to produce overestimated results. starch and starch damaged by extrusion- huge differences in the resistant starch those reported by other researchers Textural properties content in food (Perera et al., 2010). Spelt induced fragmentation increases WAI (Ra- (Núňez et al., 2009; Gałkowska et al., flour, extrudate and porridge contained yas-Duarte et al., 1988). WAI can also be 2014) but this might be due to the fact that Aqueous slurries of oat and spelt flours less available carbohydrates in compa- affected by protein macromolecules as ob- the results reported here are not ex- were flowable and showed little resistance rison to those of oats but slightly higher served by Mandge et al. (2014) who pressed in grams of starch. After ex- to back-extrusion force. The difference in content of damaged starch and less re- reported that instant multigrain porridge trusion, the endothermic peak disappeared consistency between spelt and oat por- sistant starch. The lower available carbo- increased WAI when processed at higher (Fig. 1) for both spelt and oat, suggesting ridge was not statistically significant hydrate content may be favourable in for- temperatures, causing denaturation of pro- that starch underwent complete gelatine- (p>0.05) although spelt porridge tended to mulating diets with lower dietary carbo- teins. WSI reflects on the degree of starch zation and that starch granules were fully form a firmer and more cohesive porridge hydrates but the presence of damaged degradation as it measures low molecular disrupted. This is in line with the DSC (Fig. 3). starch and less resistant starch may be weight molecules dissolved in the water thermographs of cereal and pseudocereal In contrast, the paste of extruded flours less favourable regarding glycaemic im- (Kirby et al., 1988). WSI can be a predictor flours after extrusion reported by Robin et showed remarkable increase in firmness pact. Resistant starch is not digested in of the susceptibility of food to digestion al. (2015). However, in oat and spelt ex- and cohesiveness due to increased water the human small intestine but is fermented which is important in designing weanening trudates, around 24% damaged (gelati- absorption capacity. Oat extrudates sho- in the large bowel providing numerous food for infants (Nguyen et al., 2010). nized) starch was measured by enzymatic wed an ability to form a cohesive mass. health-beneficial effects such as reduction Flours of spelt and oat showed similar WAI method (Tab. 1) which was in contrast to Higher firmness and viscosity is a desi- in the glycaemic response, cholesterol values (1.22 and 1.33 g/g, respectively) DSC data that suggested 100% gelatine- rable property in porridges (Yadav et al., reducing effect and anticarcinogenic effect whereas spelt flour had higher WSI zation. Since the content of available 2014) but quantitative guidelines on the in colon (Asp et al., 1992). On the other (7.09%) than the oat flour (3.73%). After carbohydrates is 65-69%, theoretically, the acceptable consistency of porridge does hand, damaged (gelatinized) starch is extrusion, WAI and WSI in oat and spelt remaining 40-45% could account for su- not exist (de Carvalho et al., 2014). more susceptible to digestion. Starch significantly increased. Earlier reports digestion and consequently, the metabolic suggest that WAI and WSI tend to response, depends on many factors increase after extrusion process (Ding et Table 1. Proximate composition, damaged and resistant starch contents of the oat and spelt flours, extrudates including starch gelatinization degree, pre- al., 2005; Jozinović et al., 2016). Jozinović a-e sence of indigestible polymers (dietary et al. (2016) related a post-extrusion and porridges ( Marks with different letters in the same row indicate statistical significance at p<0.05) fibres), proteins. etc. (Granfeldt et al., increase in WAI and WSI with starch Parameter Flour Extrudate Dry porridge blend 1992). To predict the real glycaemic im- damage in corn grits extrudates. Higher (% d.m.) Oat Spelt Oat Spelt Oat Spelt pact of spelt and oat porridges, it is WAI in porridges is affirmative for the Moisture 11.480.11d 11.670.10d 7.410.05a 9.960.08c 7.340.04a 8.370.04b required to study the digestible and in- production of thick porridges for people on a b b c c d Ash 1.830.07 2.290.09 2.160.08 2.620.13 2.620.11 3.310.10 digestible fractions of starch in more detail. weight-reducing diet because it would b c a d e f The porridge based on spelt may be provide adequate, thick consistency por- Proteins 13.590.04 15.870.06 12.870.03 18.010.05 29.390.08 32.390.03 e c f a d b labelled „high-fibre“ as it provides >6 g of ridge but with less calories per a portion. Fat 6.400.05 2.490.03 7.270.04 1.210.01 4.560.04 1.580.02 fibres per 100 g whereas oat porridge may The porridges had higher WSI in com- Total fibres 6.580.02b 10.160.05d 8.700.04c 12.870.05e 5.370.02a 8.890.03c bear the nutritional claim „source of fibre“ parison to the corresponding extrudates Insoluble fibres 4.350.01b 8.150.04e 5.480.03c 10.010.05f 3.430.02a 6.720.04d according to Nutritional Claims for food probably due to presence of other ingre- Soluble fibres 2.230.01b 2.010.012a 3.220.018d 2.860.02c 1.930.017a 2.170.01b (Regulation (EC) No. 1924/2006 lastly dients in their formulation. Total carbohydrates d e c d b a 78.180.27 79.350.28 77.700.20 78.160.27 63.430.27 62.7219 amended by Regulation (EU) No by calculation 1047/2012). Oat is rich in beneficial so- Thermal analysis Available carbohyd. e d d c b a 71.610.29 69.190.33 69.000.24 65.300.32 58.060.29 53.840.22 luble fibre, beta-glucan, which also sub- DSC results for the spelt/oat flours and ex- by calculation  e  e  c  d  a  b jects to labelling and is additionally advan- trudates are displayed in Tab. 3 and Fig. Damaged starch 25.52 0.25 25.84 0.22 24.10 0.20 24.72 0.19 20.78 0.21 22.43 0.18 e b f a d c tageous feature to increase the market 1. Oat and spelt flours showed a charac- Resistant starch 1.910.03 0.830.02 2.310.03 0.740.02 1.820.03 1.160.02 viability (Regulations (EU) No. 432/2012). teristic gelatinization peak (Fig. 1) which results from the gelatinization of the starch Table 2. Hydration properties a-b granules in excess water, caused by the Gelatinization temperature and enthalpy of the oat and spelt flours. ( Marks with different letters in WAI indicates the hydration properties of melting of crystalline structure of starch. the same column indicate statistical significance at p<0.05) To Tp Te H materials in excess water and is generally Oat flour showed lower onset, peak and Sample (°C) (°C) (°C) attributed to the ability of starch to absorb endset temperatures in comparison to the (J/g d.m.) Oat flour  a  a  a  a water or, indirectly, the proportion of intact spelt flour which is attributable to differen- 55.4 0.3 62.0 0.2 67.6 0.1 6.4 0.5 b b b b and gelatinized starch. Actually, it depends ces in the structure and crystallinity bet- Spelt flour 61.70.2 65.10.1 69.20.2 5.20.4

31 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018

Figure 1. Water absorption index (WAI) and water solubility index (WSI) of oat and spelt flour, extrudates and porridges Figure 3.Consistency of aqueous slurries of spelt and oat flour and reconstituted extrudates/porridges a) spelt WHO guideline recommends that porridge labelled as „source of fibre“. The flours should not drip from a spoon (WHO, had similar level of starch damage whe- 2000). Rebello et al. (2014) noted that reas spelt extrudates and porridge were high initial viscosity of instant oatmeal was significantly higher in damaged starch in associated with increased satiety and relation to the oat-based extrudate and consequently, better efficiency of appetite flour. Oat flour, extrudate and porridge control. Joshi et al. (2014) reported that were higher in resistant starch. Hydration textural properties of starch-protein com- properties of spelt extrudate and porridge posite gel/paste are strongly dependent on were better in comparison to those of oats. the ratio of starch and protein as well as Relatively high amounts of damaged (ge- on several extrinsic factors (pH, ionic latinized) starch were found in both por- strength, reducing agents, etc.). ridges (>20 g/100 g d.b.) which is due to high initial content in flour and extrusion b) oats CONCLUSION processing. The spelt porridge and extrudate had somewhat firmer consistency The results of this comparative study sho- than the oat porridge and extrudate but wed that instant oat and spelt porridges statistical significance was not reached. based on extruded oat and spelt flour sha- Oat extrudate was capable of forming a red similar features yet some differences cohesive mass. Higher hydration capacity, were observed. The spelt extrudate and firmness and cohesiveness are desirable instant porridge had more total and in- attributes in porridges. soluble fibres, proteins and minerals as well as less available carbohydrates in ACKNOWLEDGEMENTS comparison to the oat porridge. Oat extrudate and porridge were higher in soluble The authors acknowledge the financial fibre and fat. Based on the amount and support from the Ministry of Education, type of fibres found in the extrudates/por- Science and Technological Development ridges, spelt porridge may bear a label of Republic of Serbia for this work which is Figure 2. DSC Thermograms of oat and spelt flour before and after extrusion and corresponding „high-fibre“ whereas oat porridge may be the part of project III 46005. porridges

32 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018

33 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018

REFERENCES oking treatment on physicochemical and fun- vapor adsorption characteristics of freeze-dried 28. Yadav, D.N., Chhikara, N., Anand, T., Sharma, ctional properties. Journal of Food Science and rice porridge. Journal of Food Engineering, 104, M., Singh, A.K. (2014). Rheological quality of 1. AOAC (2000). Official Methods of Analysis of Technology, 51 (1), 97-103. 484-491. pearl millet porridge as affected by grits size. AOAC International, 17th Ed., Association of 15. Moussa, M., Qin, X., Chen, L-F., Campanella, 26. Robin, F., Théoduloz, C., Srichuwong, S. Journal of Food Science and Technology, 51 Analytical Chemists, Arlington, VA. O.H., Hamaker, B.R. (2011). High-quality in- (2015). Properties of extruded whole grain ce- (9), 2169-2175. 2. Asp, N.G., Van Amelsvoort, J.M.M., Hautvast, stant sorghum porridge flours for the West reals and pseudocereals flours. International 29. Zhu, L., Jones, C., Guo, Q., Lewis, L., Stark, J.G.A.J. (1996). Nutritional implications of re- African marekt using continuous processor Journal of Food Science and Technology, 50, C.R., Alavi, S. (2016). An evaluation of total sistant starch. Nutrition Research, 9, 1-31. cooking. International Journal of Food Science 2152-2159. starch and starch gelatinization methodologies 3. De Carvalho, I.S.T., Granfeldt, Y., Eliasson, A- and Technology, 46, 2344-2350. 27. WHO (2000). Complementary feeding: Family in pelleted animal feed. Journal of Animal C., Dejmek, P. (2014). Predictability of the 16. Neder-Suárez, D., Amaya-Guerra, C.A., Quin- foods for breastfed children, Department of Science, 2016.94, 1501-1507, DOI: consistency of porridges using different me- tero-Ramos, A., Pérez-Carrillo, E., de J. Alanís- Nutrition for Health and Development, France. 10.2527/jas2015-9822. thods to measure flour swelling. Starch/Stärke, Guzmán, M., Báez-González,J.G.,García-Díaz, 66, 199-207. C.L., Núñez-González, M. A., Lardizábal-Gu- 4. Ding, Q.B., Ainsworth, P., Tucker, G., Marson, tiérrez, D., Jiménez-Castro, J.A. (2016). Physi- H. (2005). The effect of extrusion conditions on cochemical changes and resistant-starch content of extruded cornstarch with and without the physicochemical properties and sensory УПОРЕДНА ИСПИТИВАЊА ФИЗИЧКО-ХЕМИЈСКИХ, ТЕКСТУРНИХ И characteristics of rice-expanded snacks. Jour- storage at refrigerator temperatures. Molecules, nal of Food Engineering, 66 (3), 283-289. 21, 1064, DOI: 10.3390/molecules21081064. ТЕРМИЧКИХ СВОЈСТАВА ИНСТАНТ КАША ОД СПЕЛТА ПШЕНИЦЕ И 17. Nguyen, VH; Mouquet-Rivier, C; Treche, S. 5. Eastman, J., Orthoefer, F., Solorio, S. (2001). ОВСА Using extrusion to create breakfast cereal (2010). Effects of starch, lipid and moisture contents on extrusion behavior and extrudate * products. Cereal Foods World, 46 (10), 468- Оливера Д. Шимурина , Бојана В. Филипчев, Бошко Д. Марић, Биљана Р. Цветковић, Марија И. 471. characteristics of rice-based blends prepared 6. FAO (2003). Methods of food analysis. In Food with a very-low-cost extruder. Journal of Pro- Бодрожа Соларов energy - methods of analysis and conversion cess Engineering, 33, 519-539. factors. FAO FOOD AND NUTRITION PAPER 18. Núňez, M., Sandoval, A.J., Müller, A.J., Della Универзитет у Новом Саду, Научни институт за прехрамбене технологије у Новом Саду, 21000 77, Report of a Technical Workshop, Rome, 3- Valle, G., Lourdin, D. (2009). Thermal cha- Нови Сад, Бул. цара Лазара 1, Србија 6, December 2002, Food And Agriculture racterization and phase behavior of a ready-to- Organization of the United Nations, Rome. eat breakfast cereal formulation and its starchy Сажетак: Промене у начину исхране и изражена склоност потрошача према здравој Retrieved on Feb. 2017, from components. Food Biophysics, 4, 291-303. храни уз раст сектора производње хране за доручак је довео до повећања понуде готових и http://www.fao.org/docrep/006/Y5022E/y5022e 19. Perera, A., Meda, V., Tyler, R.T. (2010). Re- инстант каша на домаћем тржишту. На домаћем тржишту су претежно заступљене каше од 03.htm#bm3. sistant starch: A review of analytical protocols овса. Међутим, постоје домаћи произвођачи који су заинтересовани да производе каше од 7. Gałkowska, D., Witczak, T., Korus, J., Jusz- for determining resistantstarch and of factors других жита. У складу са овом тенденцијом, циљ овог рада јесте да упореди квалитетна czak, L. (2014). Characterization of some spelt affecting the resistant starch content of foods. Food Research International, 43, 1959–1974. својства инстант каша на бази спелта пшенице и овса и на тај начин да увид у потенцијал wheat starches as a renewable biopolymeric спелта пшенице за производњу ове врсте производа. Испитиване каше су инстант производи, material. ISRN Polymer Science, 2014, ID 20. Rayas-Duarte, P., Majewska, K., Doetkott, C. 361069, 9 pages, DOI: 10.1155/2014/361069. (1998). Effect of extrusion process parameters направљени од екструдиране спелте и овса. Да би се упоредила квалитетна својства каша од 8. Gandhi, N., Singh, B. (2015). Study of extrusion on the quality of buckwheat flour mixes. Cereal спелте и овса, извршено је испитивање хемијског састава, хидратационих својстава (моћ behaviour and porridge making characteristics Chemistry, 75, 338-345. апсорпције воде и индекс растварања у води), конзистенције и термичких својстава. of wheat and guava blends. Journal of Food 21. Rebello, C.J., Chu, Y-F., Johnson, W.D., Mar- У просеку, каша од спелте је садржала више укупних и нерастворљивих влакана, протеина, Science and Technology, 52 (2), 3030-3036. tin, C.K., Han, H., Bordenave, N., Shi, Y., минералних материја и расположивих угљених хидрата у односу на овсену кашу. Каша од 9. Granfeldt, Y., Björck, I., Drews, A., Tovar, J. O’Shea, M., Greenway, F.L. (2014). The role of спелте може да се декларише као производ са високим садржајем влакана, што може (1992). An in vitro procedure based on chewing meal viscosity and oat -glucan characteristics позитивно да се одрази на комерцијализацију производа. Обе испитиване каше садржале су to predict metabolic response to starch in ce- in human appetite control: a randomized cros- сличне високе садржаје оштећеног скроба што је последица коришћења екструдираног брашна sover trial. Nutrition Journal, 13, 49, DOI: real and legume products. European Journal of у њиховој формулацији. Конзистенције каша су биле сличне, с тим да је каша од спелте имала Clinical Nutrition, 46, 649-660. 10.1186/1475-2891-13-49. 10. Joshi, M., Aldred, P., Spanozzo, J.F., Kasapis, 22. Regulation (EC) No. 1924 (2006). Regulation већу чврстоћу и кохезивност, али статистички значајна разлика није утврђена. Каша од спелте S., Adhikari, B. (2014). Rheological and micro- (EC) No 1924/2006 of the European Parliament је имала боља хидратациона својства (већа моћ упијања воде), што је једна од пожељних structural characteristics of lentil starch-lentil and of the Council of 20 December 2006 on особина, уз веће вредности за конзистенцију и кохезивност, код ове врсте производа. protein composite pastes and gels. Food Hy- nutrition and health claims made on foods. The Спелта пшеница у екструдираној форми је погодна за производњу квалитетне инстант каше. drocolloids, 35, 226-237. Official Journal of EU, Series L 404, 11. Jozinović, A., Šubarić, D., Ačkar, Đ., Babić, J., 30.12.2006, p. 9. Кључне речи: каша, спелта, овас, хидратација, састав, конзистенција, желатини- Miličević, B. (2016). Influence of spelt flour ad- (https://ec.europa.eu/food/safety/labelling_nutrit зација dition on properties of extruded products based ion/claims/nutrition_claims_en). Received: 19 April 2018 on corn grits. Journal of Food Engineeering, 23. Regulation (EU) No. 432 (2012). COMMISSION 172, 31-37. REGULATION (EU) No 432/2012 of 16 May Received in revised form: 14 May 2018 12. Khan, M.A., Semwal, A.D., Sharma, G.K., 2012 establishing a list of permitted health Bawa, A.S. (2014). Studies on the optimization claims made on foods, other than those re- Accepted: 22 May 2018 and stability of instant wheat porridge (Dalia) ferring to the reduction of disease risk and to mix. Journal of Food Science and Technology, children’s development and health. The Official 51 (6), 1154-1160. Journal of EU, Series L 136, 25.05.2012, p. 5. 13. Kirby, A.R., Ollett, A.L., Parker, R., Smith, A.C. (https://www.fsai.ie/uploadedFiles/Reg432_201 (1988). An experimental study of screw con- 2.pdf). figuration effects in the twin srew extrusion co- 24. Regulation (EU) No. 1047 (2012). The Official oking of maize grits. Journal of Food Engi- Journal of EU, Series L 310, 09.11.2013, p. 36- neering, 8, 247-272. 37. (http://data.europa.eu/eli/reg/2012/1047/oj). 14. Mandge, H.M., Sharma, S., Nabi Dar, B. 25. Rhim, J.W., Koh, S., Kim, J.M. (2011). Effect of (2014). Instant multigrain porridge: effect of co- freezing temperature on rehydration and water

34 Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based Olivera Šimurina et al., Comparative study on the physico-chemical, textural and thermal properties of instant porridges based on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018 on spelt and oats, Food and Feed Research, 45 (1), 27-35, 2018