Samh seeds powder (92.34% total solids, 19.21% total protein, 5.51% fat, 2.81% ash, 64.82% carbohydrates, and 13.29% dietary fibers) cultivated in Al-Jouf province, Saudi Arabia (KSA) was purchased from local market. Sukkari date paste (79.09% total solids, 2% total protein, 0% fat, 1.69% ash, 75.40% carbohydrates, and 8% dietary fibers) was procured from the local market in Buraydah, Qassim region, KSA. Camel milk powder (CMP: 25% total protein, 25% fat, and 40% lactose) was imported from Camelicious company, Dubi, United Arab Emirates. Whey protein concentrate (WPC: 79.17% protein, 6.25% fat, and 40% lactose) produced by Now Foods company, USA, was brought from an online supplier. The specific chemicals for each experimental method are outlined according to their respective analysis method and were subsequently described.

The current study was performed under the approval of the Committee of Research Ethics, Deanship of Scientific Research, Qassim University, Saudi Arabia (Approval No. 23-43-23). The study encompassed both in vitro and in vivo experiments. All human in vivo experiment participants were duly informed that their data would be utilized for scientific research, and everyone provided a signed consent form. The study design is visually depicted in Figure 1.

Samh five different energy balls (Figure 2) formulas were prepared depending on the chemical composition of each component used in the study, particularly total proteins and total carbohydrates content. The differences between high protein energy ball formulations are presented in Table 1. The quantities of each ingredient used to prepare the energy balls were calculated to yield 100 g each. The protein content in these energy snacks was designed to contribute at least 10% of the total calories. Consequently, the amount of ingredients, excluding date paste, was calculated to provide 8% of the total protein percentage. Each ingredient's contribution was then determined to ensure that more than 10% of the calories in each formula came from protein. The results were as follows: DS: 10.7%, DW: 12.3%, DC: 10.3%, DSW: 10.4%, and DC: 10.4%. Additionally, this formulation aimed to provide approximately 10% of the daily protein calorie needs for young adults (about 40 out of 400 kcal of protein per day), based on dietary reference values for nutrients reported by (23).

Six young, healthy adult participants (2 males and 4 females) were enrolled to assess glycemic response and their arthrometric characteristics are presented in Table 2. Following informed written consent, all volunteers underwent a comprehensive interview process. Following the criteria established by Brouns et al. (29), inclusion parameters encompassed healthy volunteers, while exclusion parameters comprised a BMI >35 kg/m², prediabetes, pregnancy, gastrointestinal disorders, gastrointestinal surgery, gastroenteritis within the preceding 6 months, smoking, or the use of any medications (30). According to the FAO/WHO guidelines (31) for glycemic response studies, the GI of food should be determined by repeated tests in at least six subjects (29). Furthermore, individuals with chronic conditions (e.g., bronchial asthma or rheumatoid arthritis) or acute illnesses (e.g., upper respiratory tract or urinary tract infection) were ineligible for participation in the study. Subjects were advised to maintain their standard diet and to avoid engaging in unusually vigorous activities until the study was concluded. It was recommended that participants stay seated and avoid excessive movement during the test (32).

Microsoft Excel 2016 and SPSS version 23 (SPSS Inc., Chicago, IL, USA) were used to analyze the data. The data were displayed as means ± standard deviations (SD). The variables of high-energy protein balls, such as the glycemic index, protein digestibility, degree of protein hydrolysis, and antioxidants, were examined by comparing one-way ANOVA. The glycemic response was analyzed using variance comparing ANOVA because the values are continuous. The participants in the study were displayed as frequency and mean.

You The data of the proximate chemical composition and nutritional value of all formulation balls are listed in Table 3. The protein content in all formulation balls ranged from 9.06 to 9.71%, except formulation balls composed of date paste, Samh powder, and camel milk powder (9.201%). As expected, date-WPC balls showed a significantly greater protein content compared to other formulation balls. This is attributed to the presence of WPC containing the highest protein level (79.14%) compared to other used ingredients. Jabeen et al. (36) found that adding whey protein isolate improved the protein level and the nutritional value of protein-energy bars. Szydłowska et al. (1) used WPC to produce high-protein organic bars with high nutritional and healthy value. Also, data presented in Table 3 shows that samples containing CMP (DC and DSC) had lower protein content compared to samples containing WPC (DW and DSW). This difference can be attributed to the higher fat content in CMP, which required a reduction in protein quantity to achieve a similar caloric contribution from protein across the various energy ball formulations, maintaining approximately 10% of the total caloric content.

Our results demonstrated that the balls formulated of date paste and camel milk powder had a significantly higher fat percentage and a significantly lower carbohydrate content than that of other formulation balls, thus because camel milk powder contains higher fat and lower carbohydrate content than other used ingredients. However, date-based Samh powder balls recorded the significantly highest carbohydrates, crude, and dietary fibers levels and this is due to Sukkari date paste and Samh seeds powder containing the greater carbohydrates (75.40% and 64.82%), dietary fibers (8.0 and 13.29%) percentages compared to other ingredients. Furthermore, the presence of crude or dietary fibers in other formulation balls is related to the relation to the amount of date paste or Samh powder that is contributed to these formulations. Siddeeg et al. (37) found that Sukkari date contain about 78.32% carbohydrates, 3.15% crude fibers, and < 1.0% fat. Mohammed et al. (11) reported that Samh seeds had 10% crude fiber and above 50% carbohydrates.

Results regarding the values of total calorie and daily values exhibited that there were significant variations among formulation balls, and the date-camel milk powder balls had the significant highest value of total calorie (366.37 Kcal/100 g ball) and daily value (18.32%). This is because of the high content of fat in camel milk powder (25%) compared to other formulation ingredients (0.0–6.25%). In addition, Sukkari date paste is a perfect source of dietary fibers that is favorable for the digestive system. Also, camel milk powder is a good source of protein (25.0%) and contains a great level of β-casein (~65% of total milk caseins). Plenty of β-casein in camel milk plays a crucial role in camel milk easy digestibility in the human body since β-casein is less impedance to proteolytic enzymes than αs-casein (38). Moreover, the moderate diameter of fat globules of camel milk is lower (2.99 μm) than that of other milk types, and this attribute makes fat globules more exposure to lipolysis, thus becoming more easily digested (39).

The total and free AAs profile of different high protein-energy balls is listed in Table 4. Our findings revealed that the addition of WPC to date-balls increased the level of AAs due to its high containing of all essential AAs (Ile, Leu, Lys, Met, Phe, Thr, and Val) and non-essential AAs including Glu, Ser, Asp, and Ala. Moreover, the ball formulations composed Samh seeds powder and WPC recorded the second formula in the total AAs content. Our results were supported by Szydłowska et al. (1), who found that the addition of WPC to high-protein bars increased the total amino acids content, particularly essential amino acids. As known, essential AAs cannot be generated by the consumer body; hence, should be provided by food. Regarding the health advantages of whey proteins, its amino acid profile is very identical to that of skeletal muscle, supplying roughly all the AAs convergent ratio to their proportions in muscles. The plenty of Leu in whey proteins is significant because of its vital role in the metabolism of protein, which has been known as a key sign in the translation inception path of muscle protein biosynthesis in the human body. In addition, Glu plays a pivotal role in the quick dividing of cells and is considered substantial through metabolic strain or sickness periods. All essential AAs should be found in each diet at adequate levels to promote the postprandial muscle protein biosynthesis process, where essential AAs are operators that have the capability to catalyze the muscle tissue anabolic pathways (40). As for Samh seeds powder was found to be rich in protein content (20–23%) and contains plenty of His, Met, Tyr, Gly, and Arg acids (16, 17).

Although fat and fatty acid residues are substantial nutritive compounds, the kind and quantity of fat consumed in the case of illness protection should not be ignored. Table 5 shows different high-protein energy balls' relative fatty acids (FAs) distribution. The highest content of saturated fatty acids (SFA) was recorded in the balls composed of date and WPC, and this was attributed to the presence of WPC, which contained 6.25% fat, while fat component was absent in date fruit. Also, these balls were rich in caprylic, capric, lauric, palmitic, and stearic acids. Vaghela and Kllara (41) reported that the commercial WPC comprised a high content of all FAs except oleic and butyric acids. On the other hand, adding Samh powder to date increased the content of unsaturated fatty acids (USFA) in balls due to the greatest level of oleic and linoleic acids in Samh powder. Ahmed et al. (42) found that the Samh seeds flour was rich in USFA, particularly linoleic acid.

Furthermore, Al-Jassir et al. (43) observed that linoleic was the predominant fatty acid in Samh seeds, pursed by oleic and palmitic acids, which agrees with our findings. It is worth mentioning that all ball formulations did not demonstrate any of the trans-fatty acids that should be decreased from their consumption due to their negative effects on human health. Their absence is attributed to the loss of industrially hydrogenated vegetable oils in the ball formulations.

The differences in the phenolic and flavonoids identified in high-protein energy ball formulations are presented in Table 6. Analysis of HPLC illustrated the presence of nine phenolic and seven flavonoid compounds at various levels in different ball formulations. Our data revealed that blending date paste with Samh powder has a significant effect on the phenolic and flavonoids compounds of ball formulations, especially p-coumaric, o-coumaric, ferulic, chlorogenic, rutin, kaempferol, myricetin, and hesperidin components. However, balls composed of date paste and WPC exhibited the highest amount of p-hydroxybenzoic, catechin, and catechol components because of the phenolic and flavonoid components of Sukkari date. In this context, Saleh et al. (25) reported that the Sukkari date contained a high content of rutin (8.10 mg/kg) and catechin (7.50 mg/kg). Alahyane et al. (44) declared that date fruits contained plenty of polyphenols, isoflavones, flavonoids, carotenoids, and phenolic acids including ferulic, caffeic, gallic, syringic, and coumaric acids. Ouamnina et al. (45) found that gallic acid was one of the prevalent phenolic compounds in date fruit. Concerning Samh seeds powder, Ahmed et al. (42) confirmed that gallic acid was the large phenolics in Samh seeds, followed by catechol, and catechin, while resveratrol was the lowest phenolics. Epidemiological studies have illustrated that consuming meals or food products enriched with phenolics could be valuable in maintaining human health or preventing difference disorders or diseases including cancer, atherosclerosis, diabetes, asthma, and cardiovascular diseases. In addition, phenolics are vastly applied in various industries for an assorted range of purposes. For instance, gallic acid acts as a food additive where its ester derivatives are combined into processed food products and a matrix of food packaging substances to maintain food products from oxidation and deterioration (46). Furthermore, it is applied as a raw substance in the industry of paints, color enhancers, inks, and pharmaceutical drugs (47–50).

The antioxidant capacity of various high-protein energy ball formulations was evaluated in vitro using two assay approaches including DPPH radical scavenging ability and reducing power (Table 7). A DPPH radical scavenging assay is a level-dependent technique; as the level of overall antioxidant compounds increases, more DPPH radical scavenging ability will occur, and vice versa. Regarding reducing power, it is a technique that depends on reducing the ferric ions/ferricyanide complicated to the Fe2+ form in the existence of antioxidant components in the antioxidant matrix. The complicated generated with blue color can be estimated at 700 nm. The results in this study indicated that the DPPH-radical scavenging ability ranged from 52.98% to 68.33% for all ball formulations without significant differences, except date-camel milk powder balls that exhibited the lowest ability. The need for digestion of bioactive substances found in camel milk proteins, including casein and whey, may stem from their requirement to be broken down in the gastrointestinal tract, as has been noted earlier (13) could be the reason. Contrariwise, somewhat significant variations among ball formulations in the reducing power values were observed. Date-Samh powder ball formulation and balls formulated of date, Samh powder and WPC showed the significantly highest reducing power value. Comprehensively, the antioxidant properties of the high-protein energy ball formulations pretend to be promptly relative to the used ingredients composition. In detail, the antioxidant capacity of Sukkari date paste and Samh powder is closely associated with the high content of phenolic and flavonoid compounds. Alfaris et al. (51) stated that various components contributed to the antioxidant properties of date including antioxidant enzymes, and considerable amounts of vitamins and minerals that can scavenge reactive oxygen species or free radicals. Hossain and Rahman (52) mentioned that the antioxidant ability of phenolics is essentially attributed to redox characteristics that make them perform as hydrogen granter agents, reducing compounds and singlet O₂ deactivators. The existence of hydroxyl groups in the phenolic compounds increases their activity (53).

Furthermore, flavonoid compounds exhibit antioxidant properties, but this capacity differs from one compound to another based on the position and number of OH groups in the B ring. Principally, an O-dihydroxylated structure of the B ring leads to great antioxidant ability due to this structure give more constancy on the aroxyl radical through the delocalization of electrons or acts as a favorable binding position for transition metal ions (45). Saleh et al. (25) declared that Sukkari dates have reducing power with 50%, and a positive correlation between total phenolic compounds and the reduction of lipid oxidation was observed. Zhang et al. (54) found that methanolic extracts of date fruits showed moderate antioxidant activity using MTT assay. Also, they observed that methanolic and water extracts of dates restrained lipid peroxidation at 58–82% and 50–67%, respectively. Concerning whey protein concentrate, the antioxidant ability may be due to the chelating of metal ions via lactoferrin and serum albumin. Furthermore, peptides or AAs of whey proteins can act as electron granter agents and might transform free radicals to more constant and may restrain lipid peroxidation through the capability of non-phosphorylated groups to chelate transition metals (55). In the last decades, whey protein concentrate or isolate products have been applied to boost the nutritional and health values of food products. Mann et al. (56) stated that supplementation of flavored milk beverages with WPC enhanced the antioxidant activity. Zeng et al. (57) reviewed the addition of whey protein products to fermented foods as having improved antioxidant activity.

The content of free NH3 groups measured by OPA assay and proteolysis degree were used to express about the intro digestibility of high-protein energy ball formulations (Table 8). Incorporating WPC in ball formulations significantly enhanced the digestibility and proteolysis degree compared to other balls free from WPC. Balls composed of date paste and camel milk powder ranked second in the digestibility and proteolysis degree. Desai et al. (58) stated that the incorporation of protein sources (WPC or camel milk powder) generated more formed bonds between carbohydrates and proteins in ball formulations, while it may obstruct the phenolics bind leading to an increment in protein digestibility. Tang et al. (59) studied the effect of equal nitrogenous component levels of casein, soy, and whey proteins on the prompting of muscle protein biosynthesis and found that the whey protein ingestion enhanced a larger increase in essential and branched-chain AAs levels in the blood than that of other protein sources. Hall et al. (60) attributed that to the rapid digestion of whey proteins. Hulmi et al. (61) and Phillips (62) confirmed that high-quality protein food products compose great concentrations of branched-chain AAs, particularly Leu acid, and these AAs are crucial promoting agents for protein biosynthesis in the human body.

Regarding camel milk, α-lactalbumin exists in high concentration and has great similarity with α-lactalbumin in human milk. Salami et al. (63) declared that α-lactalbumin of camel milk showed a greater hydrolysis degree by trypsin and chymotrypsin than that of cow milk proteins, and they proposed that α-lactalbumin of camel milk is the best substrate for proteolytic enzymes in the intestine than cow milk proteins. Zou et al. (64) and Han et al. (65) mentioned that camel milk is rich in whey acidic protein and peptidoglycan recognition protein-1 compared to cow and human milk, and these proteins display the potential to confer health benefits when digested by infants. On the other hand, Butts et al. (66) reported that vegetable proteins contain nutritional agents or factors that form a more complicated protein network, leading to a decrease in the digestibility of protein. Regarding the dairy source of proteins, the lower degree of proteolysis appearing in samples containing CMP than in samples containing WPC may be due to the presence of fat, casein and whey proteins in CMP, which may interfere during in vitro digestibility (67). This finding is supported by Khalesi et al. (68), who reported that casein is a slow-digesting milk protein, while whey protein (WP) is a fast-digesting milk protein. They also reported that heat denaturation of whey protein boosts its digestibility by making cleavage sites more accessible to pepsin, but interactions with caseins in milk protein concentrate can reduce overall protein digestibility.

The in vitro method is frequently employed as an initial assessment prior to undertaking more extensive studies on glycemic responses in human subjects. The glycemic index (GI) serves as a valuable indicator of the relative glycemic response of various foods and reflects the quality of their carbohydrate content. Glycemic load (GL) is a critical measure that evaluates the total carbohydrate impact on glucose response, incorporating both glycemic index (GI) and the overall carbohydrate content of a food item. While GI serves as an essential indicator of carbohydrate quality, it does not account for variations in individual serving sizes. Therefore, understanding GL is essential for accurately assessing the glycemic effect associated with specific portions of food. Research categorizes foods as follows: those with a GL of 10 or lower are classified as low GL, those with a GL between 11 and 20 as medium GL, and those with a GL of 20 or higher as high GL (69, 70). In this study, both the in vitro GI and the calculated glycemic load (GL) for a 25 g serving of prepared high-protein energy balls were evaluated. The results of this assessment are presented in Table 9. It clearly observed that all high-protein energy ball formulations demonstrated low GI and GL levels. However, it is important to note that significant variations were observed among the different samples. Although the per cent of total carbohydrates (Table 2) was about 71% and 69.7% in DSW and DS samples, respectively, the highest GI was for the sample formulated with date paste, Samh seeds powder and WPC (DSW: 40.219 ± 0.033), while the least was for the sample only formulated with date paste and Samh seeds powder (DS: 40.053 ± 0.019). This may be due to the presence of lactose in the WPC, which releases more glucose during in vitro digestion. Regarding the rest of the samples (DW, DC and DSC), no highly significant differences were detected in GI. As previously reported by Sulung et al. (69), several factors influence the GI of food beyond just the carbohydrate content. These factors include particle size, preparation methods, cooking techniques, food processing, the physical form of the food, and the presence of different macronutrients such as proteins and fats. Notably, having a higher proportion of protein or fat in a carbohydrate-rich meal can help mitigate the glycemic response by slowing gastric emptying and enhancing insulin secretion. In contrast, significant differences (p < 0.05) in glycemic load (GL) were observed among all samples tested. The highest GL was found in the DS sample (7.118 ± 0.004), while the lowest was in the DC sample (6.430 ± 0.003), followed by the DSC sample (6.547 ± 0.021). Additionally, the inclusion of CM powder in the formula resulted in a lower GL compared to other samples that did not contain CM powder. Previously, Mohammadabadi et al. (71) reported that the insulin-like proteins and small immunoglobulins in camel milk aid in regenerating β-cells and regulating blood glucose levels. Furthermore, these substances replicate insulin's effects and improve glucose absorption, leading to a reduction in blood glucose levels (72). The elevated GL observed in the formulation containing date paste and Samh seeds can be attributed to its principal carbohydrates: glucose, sucrose, maltose, and fructose. Notably, glucose, sucrose, and maltose exhibit higher GI values compared to lactose (70).

The association of multifunctional compounds or ingredients to prepare innovative food may change the sensory attributes of the obtained product, leading to decreased consumer acceptability. Hence, it is substantial to investigate the alterations in sensory characteristics of high-protein energy ball formulations as a result of utilizing date paste, Samh seeds powder, and different origins of milk proteins. The results of sensory assessment (Table 10) showed that all high-protein energy ball formulations were acceptable by panelists. The hedonic scale test demonstrated that the appearance, texture, and overall acceptability are recognized without significant variations among high-protein ball formulations except date paste-WPC ball (DW) formulation. Panelists gained a significant lower score for flavor of balls formulated of date paste and Samh powder or date paste and WPC compared to other ball formulations. Our findings indicated that balls formulated of date paste and WPC exhibited a soft and sticky texture, while adding Samh seeds powder to ball formulations contributed to a harder texture. Hogan et al. (73) and Szydłowska et al. (1) reported that the utilization of WPC in high-protein formulation bars maintained a softer texture of bars. Ibrahim et al. (74) found that application of date paste gave a sweet flavor to snake bars and formulation bars containing 50% date paste exhibited the highest overall acceptability and sensory attributes.

Panelists declared that more than 90% of consumers particularly athletes would purchase such balls if they available on the market. Several research works emphasize that a gap found desirable behaviors and interests on the one hand and the realistic purchase power of consumers on the other hand. Research works realize that favorable consumer buying attitude to healthy high-protein balls exists essentially among the richest consumers. Other obstacles include health and price awareness, sensitivity, the comparison between value and price, and the desire to pay. Pricing of healthy or functional food products, particularly sports products, is a multifaceted and contradictory concern because consumers desirable to buy products with low prices with high quality at the same time (75, 76). Therefore, scientific research seeks constantly to minimize the gap between consumer desires and the prices of healthy or functional products.

The term Glycemic response refers to the changes in blood glucose levels following the consumption of carbohydrates containing meals. The high levels of blood glucose after meals are associated with diet-related diseases, such as obesity, type 2 diabetes, and cardiovascular problems (70, 77).

The data illustrating the average fasting blood glucose levels, measured at baseline (0 min), alongside the blood glucose responses in healthy young adults following the consumption of a standard 50 g glucose solution and various high-protein energy balls, is presented in Figure 3. Blood glucose measurements were taken at 15, 30, 45, 60, 90, and 120 min post-ingestion (34). The results indicate the average fasting blood glucose level among the participants was 88.5 ± 7.15 mg/dL, which falls within the normal range. The postprandial blood glucose response exhibited a consistent pattern across most samples. Blood glucose levels increased from baseline, often peaking at 15 min, and returned to baseline by 120 min, except for the DSC and DSW samples. The highest blood glucose levels for both DSC and DSW were observed 30 min after ingestion. The slow gastric emptying that follows the consumption of DSC and DSW samples may explain why there is a delayed increase in blood glucose levels during the feeding state. This may occur because delayed emptying allows glucose to enter circulation gradually. This phenomenon was previously noted by Shkembi and Huppertz (70). At minute 15, the highest blood glucose levels were 140 ± 54.80 mg/dl and 139 ± 18.12917 mg/dl for DW and DS samples, respectively, while the lowest was for DSC (113± 15.14 mg/dl) and DC (120± 15.23 mg/dl) samples. The observed highest glycemic responses for the DW and DS samples may not be solely attributable to their sugar content but rather to their overall composition. As indicated by Dhaheri et al. (78), the GI is highly influenced by the levels of fructose and sucrose present. These sugars are predominant in dates, as highlighted by Alzahrani et al. (79). Consequently, it can be inferred that the higher proportion of date paste in the DW samples (90%) compared to the DS samples (59%) may be a contributing factor to their increased glycemic response concerning the other samples. All samples represented a gradual decline in blood glucose levels after 30 min, with a return to pre-meal levels observed by the 120-min mark. This data suggests that there was no occurrence of post-meal hyperglycemia. Depending on these findings, the high-protein energy balls formulated with Samh seeds powder and dairy proteins, especially from camel milk, could be recommended as a source of protein and energy food between meals for healthy young adults.