Comparison of spray, freeze and oven drying as a means of reducing bitter aftertaste of steviol glycosides (derived from Stevia rebaudiana Bertoni plant) – Evaluation of the final products

Formulation of functional gummy candies containing natural antioxidants and stevia

The research aimed to enhance the nutritional value of gummy candies by incorporating pistachio green hull extract (PGHE), stevia, and starch into the formulations. The gummy candies formulations were optimized using PGHE (1-5 %), stevia (0.013-0.040 %) and gelatin-to-starch ratio (9:1, 2:8, and 3:7) by response surface methodology (RSM), central composite design (CCD), with six center points. The physicochemical and textural properties of the gummy candies were assessed. Three optimal formulations were determined, which were preferred by the majority of panelists. One of them was selected for testing total phenolic content (680.31 ± 0.6 mg GAE/100g gummy candy), antioxidant activity (IC50 = 277 μg/mL), FTIR analysis, morphology examination, and storage stability. This study resulted in the development of gummy candies that not only offer a reduced-sugar product (50 %; equal to 12 % of sucrose) with high antioxidant activity but also eliminate the need for artificial flavors and synthetic colorants in the formulation.

Effects of Food-Derived Antioxidant Compounds on In Vitro Heavy Metal Intestinal Bioaccessibility

Environmental contamination by heavy metals (HMs) has emerged as a significant global issue in recent decades. Among natural substances, food-deriving polyphenols have found a valuable application in chelating therapy, partially limited by their low water solubility. Thus, three different hydroalcoholic extracts titrated in quercetin (QE), ellagic acid (EA), and curcumin (CUR) were formulated using maltodextrins as carriers, achieving a powder with a valuable water solubility (MQE 91.3 ± 1.2%, MEA 93.4 ± 2.1, and MCUR 89.3 ± 2%). Overcoming the problem of water solubility, such formulations were tested in an in vitro simulated gastrointestinal digestion experiment conducted on a water sample with standardized concentrations of the principal HMs. Our results indicate that regarding the nonessential HMs investigated (Pb, Cd, As, Sb, and Hg), MQE has been shown to be the most effective in increasing the HMs' non-bioaccessible concentration, resulting in concentration increases in Cd of 68.3%, in As of 51.9%, in Hg of 58.9%, in Pb of 271.4, and in Sb of 111.2% (vs control, p < 0.001) in non-bioaccessible fractions. Regarding the essential HMs, MEA has shown the greatest capability to increase their intestinal bioaccessibility, resulting in +68.5%, +61.1, and +22.3% (vs control, p < 0.001) increases in Cu, Zn, and Fe, respectively. Finally, considering the strong relation between the antiradical and chelating activities, the radical scavenging potentials of the formulations was assayed in DPPH and ABTS assays.

Instant stevia powder as a novel potential additive for enhancing nutritional value and quality characteristics of yogurt

In the current study, yogurts containing instant stevia powder (ISP) at varying proportions (0.1, 0.2, 0.3, and 0.4 g/100 mL) were perused in terms of physicochemical attributes, textural behavior, antioxidant activity, and sensory acceptability during 14 day storage at 4 °C. For this, bioactive components extracted by using microwave-assisted system were spray dried in optimum conditions (11 mL/min flow rate and 167 °C inlet air temperature) and then incorporated into yogurts. The minimal syneresis value (17.09 g/100 g) at the day of 14 was detected in ISP (0.4 g/100 mL)-supplemented yogurts while this value was reached to 19.45 g/100 g in control counterpart without stevia powder. Enriching yogurts with powders was a plausible way for boosting their mechanical properties. The antioxidative parameters namely total phenolic content (TPC), DPPH, ABTS, FRAP, and CUPRAC values were tendency to increase with ISP increment in yogurts. Low scores in sensory evaluation were detected in yogurts loaded with ISP above a certain amount (more than 0.2 g/100 mL). Sum up, the findings proved that the hypotheses (fabricating innovative dairy product rich in bioactive substances and maintaining quality parameters of yogurts during storage) predicted for this study were successfully achieved.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05892-z.

Anti-inflammatory and Antioxidant Activity of Ocimum tenuiflorum- and Stevia rebaudiana-Mediated Silver Nanoparticles: An In Vitro Study

BACKGROUND

Nanotechnology, a field bridging material science and biology, explores various applications. Silver nanoparticles, ranging from 1 nm to 100 nm, are commonly labeled as "silver," although some contain a substantial quantity of silver oxide owing to the heightened ratio of silver atoms on the surface compared to the bulk. This characteristic establishes silver as a prominent nanoparticulate material. Stevia, valued for its leaf's sweetness and purported therapeutic qualities, has been utilized for centuries in South America functioning both as a natural sweetener and in traditional health remedies. The objective of this study was to evaluate the anti-inflammatory and antioxidant activity of Ocimum tenuiflorum- and Stevia rebaudiana-mediated silver nanoparticles.

METHODS

The methods employed involved evaluating the anti-inflammatory effects using the bovine serum albumin (BSA) assay and antioxidant effects using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, with varying concentrations (10 µL, 20 µL, 30 µL, 40 µL, and 50 µL) of the nanoparticles.

RESULTS

The results indicated that the anti-inflammatory properties of the nanoparticles surpassed standard values at concentrations of 10 µL, 20 µL, and 30 µL, while the antioxidant properties were also notably surpassing standard values at equivalent concentrations. The maximum inhibition percentage was noted with 10 µL (72.5%).

CONCLUSION

The silver nanoparticles, fortified with extracts from Ocimum tenuiflorum and Stevia rebaudiana, exhibited a promising potential as effective anti-inflammatory and antioxidant agents, suggesting their viability as alternatives to commercially available products.

Meta-Topolin-induced mass shoot multiplication and biosynthesis of valuable secondary metabolites in Stevia rebaudiana Bertoni bioreactor culture

Stevia rebaudiana Bertoni possesses various medicinal and food industrial applications. This study is the first to explore the effect of the cytokinins meta-Topolin (mT; 6-(3-hydroxybenzylamino) purine), zeatin, kinetin, and BAP (6-benzylaminopurine) at concentrations of 0 (control), 5, 10, and 15 µM on shoot multiplication, as well as stevioside, rebaudioside A, phenolic acid, and flavonoid content in bioreactor cultures. The highest number of shoots (23.4 per explant) was obtained in the medium containing 5 μM of mT. However, 15 μM of mT was superior for fresh biomass production and dry biomass accumulation. Reversed-phase (RP)-HPLC analysis showed a beneficial effect of 5 μM mT on stevioside (11.43 mg/g dry weight [DW]) and rebaudioside A (10.74 mg/g DW) biosynthesis. In all conditions, the ratio of rebaudioside A/stevioside ranged from 0.75 to 1.12. The phenolic acids chlorogenic, neochlorogenic, isochlorogenic A, and rosmarinic were confirmed in the stevia extracts, as were the flavonoids isoquercetin, and quercitrin. The highest accumulations of chlorogenic and neochlorogenic acids and flavonoids were observed in shoot tissues derived from 5 µM mT, whereas 5 µM of BAP stimulated biosynthesis of chlorogenic, isochlorogenic A, and rosmarinic acids. This is the first report on the use of mT-cytokinin showing high potential in stevia cultures.

Hybridization of glucosyl stevioside and hydroxypropyl methylcellulose to improve the solubility of lutein

In this paper, a lutein-glucosyl stevioside (stevia-G)-hydroxypropyl methylcellulose (HPMC) complex was prepared via an antisolvent precipitation combined with dynamic high pressure microfluidization method. The solubility, microstructure, crystallinity and thermodynamic properties of the freeze-dried powder were investigated, as well as the formation mechanism and the storage stability of the produced complex. When the optimal mass ratio of lutein, stevia-G, and HPMC was 1: 40: 0.5, the apparent solubility of lutein reached 2805.47 ± 24.94 μg·mL^-1, which was approximately 5600 times higher than that of lutein crystals. The lutein-stevia-G-HPMC complex formed an amorphous dispersed structure and was in a thermodynamically high energy state. The self-assembled micelle structure of stevia-G and HPMC polymer created a supersaturated system mainly by multiple hydrogen bonding, which promoted maximum lutein dissolving, delayed supersaturated crystallization process, and hindered precipitation. The present results suggested the complex formed by stevia-G and HPMC effectively promote lutein's hydrophilicity and stability.

Dynamic characteristics of sweetness and bitterness and their correlation with chemical structures for six steviol glycosides

Time-intensity (TI) dynamic sensory characterization was used to evaluate the temporal sweet and bitter perception of six commonly available steviol glycosides (Rubusoside, Stevioside, Rebaudioside C, Rebaudioside A, Rebaudioside D and Rebaudioside M). All parameters extracted from TI curves significantly varied among the six samples for both sweetness and bitterness. Compared to other compounds, Rebaudioside M and Rebaudioside D had faster onset of sweetness, quicker decay of aftertaste, and were nearly devoid of bitterness. Conversely, Rubusoside and Stevioside demonstrated an immediate distinct bitter taste and lingering aftertaste. Based on these results, a further investigation into the relationship between temporal properties and chemical structures was conducted. It was found that fewer glucosyl groups on C-19 would result in shorter time for initial stimulation and longer perception of bitterness, whereas more glucosyl groups on C-13 could trigger a faster increase and stronger intensity of sweetness. A shorter time to the peak for sweetness was obtained when the ratio of the number of glucosyl groups on C-13 to that on C-19 was lower, although there was no such effect on bitter taste. These relationships were explained by the adsorption and desorption of these compounds on the taste receptors. Higher numbers and larger sizes of substitutions at the C-19 position of steviol glycosides can increase their desorption percentages and lead to a quicker decay of sweetness. Meanwhile, compounds with fewer glucosyl groups, such as Rubusoside and Stevioside, presented lower desorption and thus longer bitter aftertaste. Overall, the addition of glucosyl groups would generate stronger sweetness and less bitterness if the substituent number on C-13 was closer to that on C-19. These findings conveyed insights into how to modify steviol glycosides to enhance their quality as sweeteners.

Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves

The effect of freeze-drying and gamma irradiation at 0.5, 1, and 2 kGy on the physicochemical composition (moisture, fat, ash, mineral, and chlorophyll contents), microstructure, total phenolic content, and antioxidant capacity of stevia leaves was investigated in the present study. The results obtained indicated that freeze-drying and gamma irradiation treatments caused significant reduction ( $p$  ≤ 0.05) of moisture and fat contents in comparison with those of commercial leaves, while ash content was not significantly affected. Mineral composition was analysed. Among the analysed elements, potassium and iron levels were higher in the freeze-dried and irradiated samples, respectively. The microstructure was analysed using a scanning electron microscope. Micrographs revealed that a higher porous size structure was obtained by freeze-drying, and degradation of cell wall structure was more clearly visualized by irradiation at 2 kGy. However, the main functional groups were stable as confirmed by Fourier transform infrared spectroscopy analysis. The effects on chlorophyll content, phenolic profile, and antioxidant properties were evaluated before and after ten months of storage. In terms of chlorophyll contents, the freeze-dried leaves exhibited the highest content. Chlorophylls a and b decreased when storage progressed for freeze-dried leaves as well as for gamma-irradiated leaves. Both preservation methods gave significant advantages in increasing the total phenolic content and DPPH scavenging activity. Moreover, a significant increase of bioactive compounds and antioxidant activity was observed as the gamma irradiation dose increased. In addition, the storage time increased the amounts of polyphenols and DPPH scavenging activity. After 10 months of storage, gamma-irradiated leaves had the highest total phenolic content as well as the DPPH scavenging activity followed by freeze-dried leaves. The results indicate that freeze-drying and gamma irradiation at the studied doses could be effective postharvest methods for preservation of stevia leaf quality.

Manufacturing of Plant-Based Bioactive Peptides Using Enzymatic Methods to Meet Health and Sustainability Targets of the Sustainable Development Goals

Due to the rapid growth in the global population, the consumption of animal-based food products/food compounds has been associated with negative implications for food sustainability/security. As a result, there is an increasing demand for the development of plant-based food and compounds as alternatives. Meanwhile, a growing number of studies report the health benefits of food protein-based peptides prepared via enzymatic hydrolysis and exhibiting biological properties such as antioxidant, antihypertensive, anti-thrombotic, and antidiabetic activities. However, the inherent bitterness of some peptides hinders their application in food products as ingredients. This article aims to provide the latest findings on plant-based bioactive peptides, particularly their health benefits, manufacturing methods, detection and qualification of their bitterness properties, as well as debittering methods to reduce or eliminate this negative sensory characteristic. However, there is still a paucity of research on the biological property of debittered peptides. Therefore, the role of plant protein-derived bioactive peptides to meet the health targets of the Sustainable Development Goals can only be realised if advances are made in the industrial-scale bioprocessing and debittering of these peptides.

Recent developments in vibrational spectral analyses for dynamically assessing and monitoring food dehydration processes

Dehydration is one of the most widely used food processing techniques, which is sophisticated in nature. Rapid and accurate prediction of dehydration performance and its effects on product quality is still a difficult task. Traditional analytical methods for evaluating food dehydration processes are laborious, time-consuming and destructive, and they are not suitable for online applications. On the other hand, vibrational spectral techniques coupled with chemometrics have emerged as a rapid and noninvasive tool with excellent potential for online evaluation and control of the dehydration process to improve final dried food quality. In the current review, the fundamental of food dehydration and five types of vibrational spectral techniques, and spectral data processing methods are introduced. Critical overtones bands related to dehydration attributes in the near-infrared (NIR) region and the state-of-the-art applications of vibrational spectral analyses in evaluating food quality attributes as affected by dehydration processes are summarized. Research investigations since 2010 on using vibrational spectral technologies combined with chemometrics to continuously monitor food quality attributes during dehydration processes are also covered in this review.

The aplication of Pistacia khinjuk extract nanoemulsion in a biopolymeric coating to improve the shelf life extension of sunflower oil

In the present study, a hydroalcoholic extract of P. khinjuk was obtained by sonication method at 60°C for 50 min. The measurement revealed that the total phenolic content of the extract was 46.0 mg/g. The results showed that the extract has an antioxidant activity of 73.5% and 8.3 (µmol TE/g DW) in DPPH radical scavenging method and FRAP assay, respectively. Also, Balango (Lallemantia royleana) and Fenugreek (Trigonella foenum-graecum) seed gum and their composition (1:1) were used to prepare the nanoemulsion with P. khinjuk extract. The droplet mean size of nanoemulsions was ranged from 310.34 to 354.19 nm. The highest encapsulation efficiency was observed in Balango nanoemulsion. P. khinjuk extract nanoemulsion coating with Balango and TBHQ was added to sunflower oil at 200 and 100 ppm, respectively. During 24-day storage at 60°C, samples were investigated for peroxide, acid, and p-anisidine values at 4-day intervals. The results showed that oils containing nanoemulsion had the highest stability during storage. However, in all samples peroxide, acid and p-anisidine values increased but the rate of oxidation in samples containing both synthetic and natural antioxidants was slower than the control sample.

Spray drying encapsulation of stevia extract with maltodextrin and evaluation of the physicochemical and functional properties of produced powders

This work aimed to formulate and perform physicochemical and functional characterization of maltodextrin microcapsules containing ethanolic extract of stevia, rich in antioxidant compounds, encapsulated by a spray-drying process with two maltodextrins (DE10 and DE19). The powders were named M10 and M19, respectively. We analyzed the physicochemical parameters, antidiabetic activity, cytotoxicity, bioaccessibility of the compounds by in vitro digestion, as well as the structure of the microcapsules by scanning electron microscopy. Microcapsules showed higher solubility (∼35%), lower moisture content (∼29%), and the maltodextrin DE10 had higher efficiency as an encapsulating agent (87%) when compared to DE19 (76%) and showed well-defined spherical structures. The microencapsulation preserved the content of phenolic compounds and antioxidant activity present in the extract (7.2% and 87.5%, respectively). The bioaccessibility of these microencapsulated compounds and antioxidant activity were higher under different conditions of in vitro digestion (mouth, gastric, and intestinal conditions) and showed no cytotoxic effects. We identified 41 compounds (by UHPLC-MS/MS-Qtof) related to the nutritional benefits offered by stevia and the microencapsulation technique can be recommended to preserve bioactive compounds. PRACTICAL APPLICATION: Ethanol extract from stevia leaves contains antioxidant phytochemicals related to the nutritional benefits of stevia. However, this extract presents low solubility and consequently low bioaccessibility under in vitro digestion. The microencapsulation process protects the bioactive compounds of the different pH from digestion and improves the physical-chemical parameters of the extract, increasing its applicability as a possible food additive.

Effect of Growth Regulators on Stevia rebaudiana Bertoni Callus Genesis and Influence of Auxin and Proline to Steviol Glycosides, Phenols, Flavonoids Accumulation, and Antioxidant Activity In Vitro

Stevia is a plant containing many active compounds, but usually propagated by stem cuttings because of low seed-yield-germination ability. The aim of this study was to investigate the impact of plant-growth regulators on stevia callus induction and growth from somatic tissue, as well as to determine the effect α-naphthalene acetic acid (NAA) and proline (PRO) on the amount of stevioside, rebaudioside A, phenols, flavonoids, and antioxidant activity. Stem and leaf segments were inoculated on a Murashige and Skoog (MS) medium supplemented with different concentrations of NAA and 6-benzylaminopurine (BAP) for callus genesis. The amount of steviol glycosides (SGs) was evaluated using high-performance liquid chromatography (HPLC), and the amounts of total phenols, flavonoids, and antioxidant activity by spectrophotometric methods. The highest callus-induction frequency and callus-mass increase were obtained from the leaf explants in MS medium supplemented with 2.0 μM NAA. The highest amount of SGs, phenols, and flavonoids, and stronger antioxidant activity were determined in the cellular compounds of callus from leaf explant. PRO reduced the amount of SGs and flavonoids. The significantly highest amount of total phenolic compounds was obtained in the callus from leaf explants in the medium supplemented with 2.0 µM NAA and 2.0 µM PRO.

The application of unconventional technologies as pulsed electric field, ultrasound and microwave-vacuum drying in the production of dried cranberry snacks

A lot of effort is put to decrease the energy consumption of drying. This effect might be achieved by shift of a drying technology e.g. from a hot-air to a microwave-vacuum method. Moreover, an unconventional pre-treatment such as ultrasound or pulsed electric field may modify a cellular tissue, what influences drying kinetics of plant tissue. The aim of the study was to analyse the quality of microwave-vacuum dried, osmodehydrated (OD) cranberries processed by the means of blanching and ultrasound (US) or blanching followed by pulsed electric field and sonication (PEF + US) in comparison to traditionally treated material. Physical, chemical and sensorial properties of cranberry fruits were assessed. What is more, the impact of aforementioned unconventional treatments on the kinetics of microwave-vacuum dried cranberries was studied. Microwave-vacuum drying process was very short (25-38 min) in comparison to convective drying, which lasted several hours (13.2 h). Most of the samples subjected to US and PEF + US treatments before OD and drying were characterized by similar or a higher amount of bioactive compounds such as polyphenols, anthocyanins and flavonoids, and better colour and taste, as compared to cut osmodehydrated cranberry fruits subjected to convective drying (reference samples).

The Application of Combined Pre-treatment with Utilization of Sonication and Reduced Pressure to Accelerate the Osmotic Dehydration Process and Modify the Selected Properties of Cranberries

The aim of this study was to investigate the effect of a pretreatment, performed by a combined method based on blanching, ultrasound, and vacuum application, on the kinetics of osmotic dehydration and selected quality properties such as water activity, color, and bioactive compound (polyphenols, flavonoids, and anthocyanins) content. The pretreatment was carried out using blanching, reduced pressure, and ultrasound (20 min, 21 kHz) in various combinations: Blanching at reduced pressure treatment conducted three times for 10 min in osmotic solution; blanching with reduced pressure for 10 min and sonicated for 20 min in osmotic solution; and blanching with 20 min of sonication and 10 min of reduced pressure. The osmotic dehydration was performed in different solutions (61.5% sucrose and 30% sucrose with the addition of 0.1% of steviol glycosides) to ensure the acceptable taste of the final product. The changes caused by the pretreatment affected the osmotic dehydration process by improving the efficiency of the process. The use of combined pretreatment led to an increase of dry matter from 9.3% to 28.4%, and soluble solids content from 21.2% to 41.5%, lightness around 17.3% to 56.9%, as well as to the reduction of bioactive compounds concentration until even 39.2% in comparison to the blanched sample not subjected to combined treatment. The osmotic dehydration caused further changes in all investigated properties.

Effect of freeze- and spray-drying on physico-chemical characteristics, phenolic compounds and antioxidant activity of papaya pulp

The effect of freeze- and spray-drying on physico-chemical characteristics, phenolics compounds and antioxidant activity of papaya pulp was investigated. The frozen pulp was freeze dried at - 62 °C during 48 h. Papaya pulp with 14% DE maltodextrin was also dried in a spray dryer. The organic acids, sugars, color, total soluble solids, pH, carotenoids, phenolic and flavonoid compounds, and antioxidant capacity values were determined. The changes in color, pH and lycopene were negligible. However, lower retention (86.5%) of vitamin C and sugars (glucose-79.7% and fructose-66.1%) was observed in spray dried products. Phenolic and flavonoid compounds were identified and quantified in dried papaya products by UHPLC-QqQ-MS/MS. Spray dried products presented a higher retention of phenolic and flavonoid compounds compared to the freeze dried products. Despite some variations in the parameters studied, the use of freeze- and spray-drying has proven viable options for the drying of papaya pulp.

Zùsto: A new sweetening agent with low glycemic index

BACKGROUND & AIMS

Sweetening agents are sugar substitutes with a low glycemic index, used to obtain a better glycemic control in diabetes patients. However, they also may have a role in other subjects, as a high glycemic index is thought to cause many pathological conditions. Unfortunately, not all artificial sweeteners are perceived as sweet as sugar by patients. Consumers refer often to an after taste present in foods sweetened with intensive sweeteners. The objective of this study was to explore whether Zùsto^® had a low glycemic index, to replace glucose as a sweetener.

METHODS

In this study, the glycemic index (GI) of a new sweetening agent, Zùsto^®, is compared to that of glucose 25 g, a standard sugar-loaded drink used in the oral glucose tolerance test to detect diabetes, as primary endpoint. Zùsto^® is composed of non-digestible, water soluble fibers and sweeteners. 10 healthy, female non-obese volunteers received glucose and Zùsto^®, albeit by an interval of a week. Evolution of glycemia, C-peptide and insulin release was measured at different time-points after intake.

RESULTS

The results show that, when calculating the mean incremental Area Under the Curve (AUC), the AUC of glucose was around five times as high as that of Zùsto^®; a GI of 22 for Zùsto^® was calculated. Furthermore, Zùsto^® had no significant effect on the glycemia, contrary to glucose, for at least 60'. This was also the case concerning C-peptide and insulin release, but the difference lasted even for 180'. Moreover, Zùsto^® was perceived as sweet by all volunteers, with no particular aftertaste.

CONCLUSION

Zùsto^® could be a viable alternative for fast sugars and other sweetening agents, both for diabetic patients and other subjects, requiring however a larger trial to confirm these results. CLINICALTRIALS.GOV: NCT02607345.

Evaluation of different agroindustrial waste on the effect of different carcass characteristics and physiological and biochemical parameters in broilers chicken

Aim:

This study was conducted to evaluate the physiological and biochemical effect in chickens of the Ross breed of a food enriched with agroindustrial waste.

Materials and Methods:

The food is one of the main components of the total cost for the production of chickens. Rations should be formulated to provide the correct balance of energy, protein, amino acids, minerals, vitamins and essential fatty acids, to allow optimal growth and performance. This study was intended to evaluate a natural feed for chicken, made from corn, yucca meal, eggshells, orange peel, soybean meal, salt and garlic, enriched with agroindustrial waste (molasses, milk whey and ferment of coffee). The weight gain was evaluated in broilers using a diet enriched with different agroindustrial wastes, with respect to a control food of the same composition but not containing residue. To develop the experiment 120 male Ross 308 chicks were used, these were evaluated for 6 weeks. Physicochemical test for the food and the agroindustrial waste were performed; moisture was determined; organic carbon, organic material and the ash, to characterize the agroindustrial wastes, the reducing sugars content using a spectrophotometer at 540 nm and proteins through the Kjeldahl method was evaluated. During the experiment, the weight gain of chickens and feed conversion was evaluated; the end of the experiment the weight of eviscerated channel relative weight breast, thighs, pancreas, and abdominal fat was determined, besides including blood chemistries as determination of cholesterol, triglycerides, and glucose. Finally, the microbiological analyzes to detect the presence of Escherichia coli in the cecum was determinate. Data were analyzed by InfoStat statistical program using the generalized linear model procedure. The statistical comparison was made by Tukey test at the 95% probability level.

Results:

After the evaluation, fed chickens with the treatments food + milk whey (FMW) and food + ferment of coffee (FFC) demonstrated increased from 1949 to 1892 g, respectively, to the 42 days of evaluation, showing the best treatment for weight gain. However, the FFC treatment showed the best feed conversion reaching values of 1.79 related to levels of blood glucose (249 mg/dl). Even so the eviscerated channel yields were higher for the treatment FFC reaching 1810.1 g unlike the treatment FMW which it reached a weight of 1718.2 g with increased formation of abdominal fat (7.4 g) unlike other treatments. From the results, it is concluded that food enriched with coffee ferment allows an increase in weight, better feed conversion in addition to high production of lean meat.

Conclusion:

It was shown that the best treatment was the food enriched with the ferment of coffee, due to increased intake and weight gain at the end of 42 days of the experiment.

Comparative Study on Different Drying Methods of Fish Oil Microcapsules

Microencapsulation is widely used to minimize the oxidation of fish oil products. This study compared the effects of different drying methods, for example, spray drying (SD), freeze drying (FD), and spray freeze drying (SFD) on the microencapsulation of fish oil. Spray drying (SD) is the most common method for producing fish oil microcapsules, and it has low operation cost and short processing time, while the product yield and quality are poor. Freeze drying (FD) can be used to produce oil microcapsules with high quality, but it takes long time and high overall cost for drying. Spray freeze drying (SFD) is a new method for the preparation of microcapsules, which combines the SD and FD processes to obtain high quality powder. The yield of powder reached 95.07% along with porous structure by SFD. The stability and slow-release property of SFD products were better than those of SD and FD, which showed that SFD improved product storage stability and potential digestibility.

Stevia Glycosides: Chemical and Enzymatic Modifications of Their Carbohydrate Moieties to Improve the Sweet-Tasting Quality

Stevia glycosides, extracted from the leaves of the plant Stevia rebaudiana Bertoni, display an amazing high degree of sweetness. As processed plant products, they are considered as excellent bio-alternatives for sucrose and artificial sweeteners. Being noncaloric and having beneficial properties for human health, they are the subject of an increasing number of studies for applications in food and pharmacy. However, one of the main obstacles for the successful commercialization of Stevia sweeteners, especially in food, is their slight bitter aftertaste and astringency. These undesirable properties may be reduced or eliminated by modifying the carbohydrate moieties of the steviol glycosides. A promising procedure is to subject steviol glycosides to enzymatic glycosylation, thereby introducing additional monosaccharide residues into the molecules. Depending on the number and positions of the monosaccharide units, the taste quality and sweetness potency of the compounds will vary. Many studies have been performed already, and this review summarizes the structures of native steviol glycosides and the recent data of modifications of the carbohydrate moieties that have been published to provide an overview of the current progress.