Dry CHS were cleaned from impurities and odd materials. Dry cleaned seeds (10 g/1L beverage) were soaked in sufficient quantity of distilled water, then left for 30 min with frequent stirring until inducing full water absorption at ambient temperature (25˚C ± 5˚C).

CMC and XG solutions were prepared by dissolving 0.05 and 0.1 g each from CMC and XG in 100 ml distilled water and were stirred with a magnetic stirrer for 10 min and till it was completely dissolved at ambient temperature.

GG solution was prepared by dissolving (0.05 g and 0.1 g) in 100 ml hot distilled water at 85˚C and adding 0.05 g calcium chloride to each solution then it was continuously stirred with a magnetic stirrer for 5 min until it was completely dissolved at 85˚C.

The preparation and processing operations of mango beverage (MB) and mango flavored beverage (MFB) were conducted in the laboratory of Edfina Company for preserved foods, according to the Egyptian standard (No. 1602/2017) as follow:

1) Preparation of mango beverage (MB)

Mango fruits were carefully washed using tap water and were well drained. The skin and seeds were removed manually, then the pulp was cut into small pieces. These pieces were blended with a little water by a blender (Kenwood major blender, Japan) to obtain the mango puree (total soluble solids (TSS) 15˚Brix). Mango puree was packed in plastic bags, (each bag weighs 1 kg.), then stored at −18˚C until further use. The basic formula to produce 1 L of MB, was 100 g mango puree which represented (10%), 105 g sugar, 1.5 g citric acid, 0.25 g ascorbic acid and 783 ml water.

2) Preparation of mango flavored beverage (MFB)

The basic formula of MFB was 120 g sugar, 1.5 g citric acid, 0.25 g ascorbic acid, 0.15 g beta carotene as natural coloring agent, 1.5 g mango flavor and 867 ml water, then the ingredients were well mixed.

Various preliminary experiments (sixteen samples) were performed to select the best concentrations of hydrocolloids used in this investigation, that make high suspension stability of CHS distributed in their beverages during storage for 48 h at ambient temperature, (25˚C ± 5˚C). The samples were prepared as follows:

1) One sample of MB and one sample of MFB were prepared as described by the Egyptian standard.

2) One sample of MB + CHS was prepared mango beverage-chia seeds (MB-CHS) and considered as control sample (C₁).

3) One sample of MFB + CHS was prepared mango flavored beverage-chia seeds (MFB-CHS) and considered as control sample (C₂).

4) Two samples of MB-CHS + 0.05% or 0.1% CMC.

5) Two samples of (MFB-CHS) + 0.05% or 0.1% CMC.

6) Two sample of MB-CHS + 0.05% or 0.1% XG.

7) Two sample for MFB-CHS + 0.05% or 0.1% XG.

8) Two sample for MB-CHS + 0.05% or 0.1% GG.

9) Two sample for MFB-CHS + 0.05% or 0.1% GG.

The components were mixed and stirred well at ambient temperature for uniformity, and TSS of all beverage samples were set at 12˚Brix by using a refractometer. All beverage samples were heated to 90˚C, then the hot solutions were placed in sterilized glass bottles and sealed. The glass bottles were kept at 85˚C for 10 min in a water bath, then cooled to room temperature in an icy water bath. After 48 h of storage period at ambient temperature, viscosity, color and sensory attributes were measured.

According to the results obtained from the preliminary experiments, the best-chosen treatments were: MB-CHS with 0.05% GG, 0.1% XG and 0.1% CMC; MFB-CHS with 0.05% GG; compared to the control samples C₁ and C₂.

All processing operations relied on the implementation of hygienic requirements. The chosen samples were packed into 200 ml of sterilized clear glass bottles, then heat treatment at 90˚C for 10 min in a hot water bath, tightly closed, then directly cooled by icy water bath. Samples were kept at ambient temperature (25˚C ± 5˚C) for six months storage period.

CHS were ground in a grain mill (Kenwood multi mill, Japan) and sieved to pass through 60 mesh sieves, then packed in glass jars and stored at 4˚C until analysis. Total solids, ash and crude fiber contents were determined according to [13] . The analyses of CHS, MB, MFB, MB-CHS with 0.05% GG and MFB-CHS with 0.05% GG were carried out as follows: crude protein, crude oil and total dietary fiber contents were determined according to the method of [13] . Carbohydrate was calculated by difference. Caloric value was calculated using the universally acceptable conversion factors by multiplying protein and carbohydrates by 4.00 and fat by 9.00 Kcal/g. Potassium was determined using flame photometer (Model PEP7, England), while calcium, magnesium, iron, zinc, manganese and copper were determined using Perkin Elmer Atomic Absorption Spectrophotometer Model 2380 [14] . The fatty acid composition of CHS was investigated by Gas Liquid Chromatography (GLC). The chia oil was esterified before GLC analysis using the method described by [15] . The chromatogram of the authentic fatty acids was used to characterize the fatty acids according to their retention times. Fatty acid composition was expressed as a percentage of the total fatty acids [16] .

Viscosity was measured with a rotary viscometer (Brookfield Model DV-II + Pro, USA) at the speed of 60 rpm and spindle number 2 [17] . The color attributes of MB-CHS and MFB-CHS were measured using a colorimeter (Hunter L^* a^*, b^*, Ultra scan vis, USA) with a tristimulus absorption filter. The tristimulus coordinates: L^* (lightness), a^* (redness), and b^* (yellowness) were measured [18] .

CHS were separated from beverages and the filtrate was filled in cuvettes in order to measure the zeta potential using a zetasizer (Zetasizer Zen3600, Malvern Instruments Ltd, UK) according to [19] .

To measure the stability of CHS in beverage height percentage of seeds was visually measured during 48 h and six months of storage compared to the control samples (C₁ and C₂) using the following equation [19] .

Heightpercentageofseeds ( % ) = Heightofseeds Totalsampleheightinthebottle × 100

The best-chosen samples depended on the results of suspension stability of CHS after 48 h of storage.

The tests of sensory parameters in the preliminary and basic experiments were conducted using a 9-point hedonic scale [20] . The judgment was accomplished by 20 panelists, including 10 panelists from Food Technology Laboratory, of Sabahia, Alexandria, Egypt, Food Technology research institute (FTRI) and 10 panelists from Edfina company, Alexandria, Egypt. Samples were presented to the panelists in 250 ml clear bottles, that were randomly coded. The sensory attributes evaluated were color, taste, texture, mouthfeel, appearance & suspension of seeds and overall acceptability.

All analysis were triplicate, except for fatty acids, colorimetric measurements and zeta potential measurements, and were expressed as mean values ± standard deviation. Statistical analyses were carried out using software (SAS) version 9.1 (SAS Institute Inc., Cary, NC) [21] . Statistical analyses were performed using one-way analyses of variance followed by Duncan’s test. Differences were considered significant at p ≤ 0.05.

The effect of hydrocolloid type and its concentration on the viscosity of studied beverages, after 48 h of storage at ambient temperature, as preliminary experiments were shown in Figure 1. It could be observed that the lowest viscosity was in C₂ (26 cps) followed by C₁, which recorded (28 cps). The low viscosity is due to the absence of hydrocolloid, Figure 1. The samples of MB-CHS recorded higher viscosity than MFB-CHS as compared with samples containing the same

type and concentration of hydrocolloids. This difference may be due to using natural mango pulp for processing of MB-CHS. The addition of CMC, XG and GG at the concentration of (0.05% and 0.1%) in MB-CHS and MFB-CHS samples, led to significantly higher viscosity (P ≤ 0.05) as compared with C₁ and C₂, respectively. This means that, increase of hydrocolloid concentration led to the increase of beverage viscosity. These results agree with those by found of [27] who mentioned that increasing the concentration of gum in drinks caused a direct proportional increase in the viscosity and sensory perception. The highest viscosity was observed in MB-CHS and MFB-CHS containing GG 0.1%, they were (460 cps and 340 cps), respectively. The high viscosity led to formation of hard gel of the studied beverages. These results were in agreement with [28] who stated that if the concentration of the gellan gum is sufficiently high, then the double helices form can further transform into thicker rod-like aggregates leading to the formation of a macroscopic gel.

The influence of using CMC, XG and GG at the concentration of 0.05% and 0.1% compared with the control sample on the stability of suspension of CHS in MB and MFB during storage 48 h is illustrated in Figure 2(a) and Figure 2(b). C₁ and C₂ as control samples recorded the lowest percentage of stability and suspension, while the samples containing CMC and XG at the concentration of 0.05% gave a weak stability. The fast rate of seeds sedimentation was observed in the sample of MFB-CHS during the first hour of storage, and the best stability and suspension of seeds was observed in MB-CHS; these results were due to using the natural pulp of mango fruit in the processing of MB. In both MB-CHS and MFB-CHS beverages, the addition of GG (0.05% and 0.1%) led to the increase

stability and suspension of seeds, also the addition of 0.1% XG and 0.1% CMC in MB-CHS gave the high stability and suspension of seeds. While no effect was noticed on the stability of MFB-CHS. No significant difference in stability was observed between the three hydrocolloids when added to MB-CHS. These results agree with [29] who reported that XG is effective in suspending fruit pulp for long periods. [30] mentioned that GG fluid gels can be used to produce shelf stable suspensions in a variety of beverages products.

The effect of different types and concentrations of hydrocolloids on color values (L^*, a^* and b^*) of beverages after processing in storage for 48 h at 25˚C ± 5˚C are given in Table 2. A slight decrease was shown in the L^* value in all treatments compared with controls (C₁ and C₂), while, this decrease of these values was higher by adding XG and GG compared with the sample containing CMC. This means that addition of XG and GG, led to color stable of beverages. These results agree with [31] and [32] , who found that the presence of GG and XG had increased the stability of acerola smoothie and red rice drinks pigments such as anthocyanins and carotenoids when compared to the control. For the values a^* and b^*, all treatments have higher values than the control, however, change the concentrations from 0.05% to 0.1% of hydrocolloids had not effect on L^*, a^* and b^* values in all the studied samples, these results are in agreement with [33] .

After storage at ambient temperature for 48 h the average scores for the parameters

L^*: lightness; a^*: redness; b^*: yellowness; MB-CHS: mango beverage-chia seeds; MFB-CHS: mango flavored beverage-chia seeds; CMC: carboxymethyl cellulose; XG: xanthan gum; GG: low acyl gellan gum; C₁: mango beverage without gum; C₂; mango flavored beverage without gum.

of sensory attributes of MB-CHS and MFB-CHS containing hydrocolloids at concentration of 0.05% and 0.1% are presented in Table 3. There were no significant differences (p ≥ 0.05) among treatments for color and taste after 48 h of processing. The texture and mouthfeel satisfaction increased with the addition of 0.05% GG, 0.1% CMC and 0.1% XG, while there was significant decrease (p ≤ 0.05) of these properties when 0.1% GG was added to MB-CHS and MFB-CHS, and that was reflected in the decision of panelists, who disliked the samples with 0.1% GG. These results were confirmed with viscosity analyses Figure 1. With increasing CMC and XG concentration in MB-CHS, the appearance and suspension of seeds increased (p ≤ 0.05). On the other hand, 0.05%, 0.1% GG gave highest scores and were extremely liked concerning appearance and suspension of seeds in MB-CHS and MFB-CHS. The overall acceptability recorded the highest score for the treatment containing 0.05% GG of both beverages followed by the treatments containing 0.1% XG and 0.1% CMC when added to MB-CHS sample. These results agree with [29] and [28] , they reported that XG and GG imparted a drink-enhanced mouth feel with a full-bodied taste and good flavor release.

MB-CHS: mango beverage-chia seeds; MFB-CHS: mango flavored beverage-chia seeds; CMC: carboxymethyl cellulose; XG: xanthan gum; GG: low acyl gellan gum; C₁: mango beverage without gum, C₂: mango flavored beverage without gum; Different superscripts in the same column are significant differences at P ≤ 0.05 level.

From the previous results of preliminary experiments, the best treatments were chosen according to the resulted of stability of suspension CHS, non-sedimentation, color values, uniformity as well as the organoleptic properties of studied beverages. This was an indicator to conduct the basic experiments and the chosen treatment were as follows: CHS with (0.05% GG, 0.1% XG and 0.1% CMC) for preparing MB-CHS and CHS with 0.05% GG for preparing MFB-CHS and then studying their behavior during storage for six-months at ambient temperature (25˚C ± 5˚C).

The effect of the gum types on the suspension of CHS in MB and MFB during the storage period of six months are shown in Figure 3(a) and Figure 3(b). All beverages recorded high stability of suspension of CHS in the initial time of storage Figure 2(a) and Figure 2(b). The control samples (C₁ and C₂) recorded low stability of suspension of seeds and fast rate of seeds sedimentation.

During storage period of six months, the beverage containing 0.05% GG in MB-CHS (Figure 3(a)) and MFB-CHS (Figure 3(b)) recorded high stability of suspension of CHS, followed by 0.1% XG in MB-CHS, which recorded high stability of suspension of seeds at the initial two months of storage, and showed a

significant decrease (P ≤ 0.05) by the increase of storage period for six months. During the storage period, the suspension of seeds in beverages containing CMC 0.1% significantly decreased (P ≤ 0.05) by increasing storage time as compared with 0.05% GG and 0.1% XG. These results showed that the use of 0.05% GG led to highest stability and the best appearance of suspension of CHS during six months of storage (visual observation), as they almost fully retained their physical properties during storage. These results agreed with those reported by [34]

Dispersed systems such as colloidal suspensions contain electrically charged particles that interact with each other and with the media, these amounts of charges are called zeta potential, and are used to gauge how stable is colloidal system [35] . As shown in Figure 4, the zeta potential values for all samples were clearly negative, indicating that there are more negatively charged particles than positively charged particles in all beverages; this was attributed to the existence of beverage particles with positively charged carbohydrate and protein nuclei surrounded by negatively charged pectin (C₁ and C₂) as well as to the properties of added stabilizers to the samples [33] . Furthermore, the absolute value of zeta potential of the beverage samples with XG, CMC or GG were higher than that of the control (C₁; −14 and C₂; −12 MV). This is because the XG, CMC and GG are anionic polysaccharides and thus provide a certain amount of negatively charged particles, [32] [36] . In the initial time, the sample containing 0.1% XG recorded higher value of zeta potential (−27.1 MV) followed by 0.1% CMC (−22.2 MV), while the sample containing 0.05% GG recorded the lowest value (−21.4 MV in MB-CHS and −21 MV in MFB-CHS). These results may be due to adding double

concentration of XG and CMC compared with GG. These results agreed with [37] and [33] who mentioned that the absolute zeta increased with the increase in hydrocolloid concentration due to the anionic properties of hydrocolloids. During the storage period for one-month, absolute zeta slightly decreased in all samples. This change in zeta may be due to the exit of protein with positive charge from CHS [38] . Zeta value in C₁ and C₂ decreased after one month then become stable tell six months of storage, while in beverage with different gum types, zeta potential showed a decreased after one month then increased after three months, these may be due to the anionic and adsorbing properties of the existing hydrocolloids (XG, CMC and GG). Finally, is become stable tell the end of storage for six months. Similar outcomes have been attained when pectin, gum tragacanth, CMC, XG and GG were used as stabilizers in juices and dairy products [37] and [39] . Although the samples of 0.05% GG recorded lower zeta potential but it had the highest stability of seeds suspension, these results agree with [40] who mentioned that, it is common to find stable systems with low absolute zeta potential values and vice versa.

The sensory attributes of the selected beverages after storage for six months are illustrated in Figure 5(a) and Figure 5(b). Generally, the beverages containing 0.05% GG in MB-CHS and MFB-CHS recorded the highest mean scores for all parameters compared to other treatments, was most acceptable from the organoleptic point of view and kept the suspension of seeds even at the end of six months of storage. These results confirmed by the result of seed suspension in Figure 3. The sensory scores of all beverage samples decreased after six months of storage period as compared to those evaluated after 48 h of storage shown in Table 3. The control beverage C₁ in MB-CHS and C₂ in MFB-CHS had the lowest scores of all parameters compared to the other samples and showed a decreased acceptability after six months of storage (Table 3 and Figure 5). The

%DV: % Daily Value; MB: mango beverage; MFB: mango flavored beverage; MB-CHS: mango beverage-chia seeds; MFB-CHS: mango flavored beverage-chia seeds.

overall acceptability of the beverage containing 0.1% CMC in MB-CHS decreased with increasing storage time followed by the treatment containing 0.1% XG.