Protein Hydrolysate Powder Research Articles

Effect of Hydrodynamic Cavitation and Drying Technique on Moisture Sorption Isotherm and Structural Properties of Egg White Protein Hydrolysate Powder

Effect of Hydrodynamic Cavitation and Drying Technique on Moisture Sorption Isotherm and Structural Properties of Egg White Protein Hydrolysate Powder

Effects of cluster dextrin encapsulation on the properties and antioxidant stability of fractionated Riceberry protein hydrolysate powder prepared by bromelain

In this work, the biological properties of fractionated Riceberry bran protein hydrolysate obtained by ultrafiltration (URBPH) were evaluated and the possibility of using cluster dextrin to produce hydrolysate powder by spray-drying was investigated. Fractionation into peptides < 3 kDa was observed to improve antioxidant activity. URBPH < 3 kDa was then freeze-dried (FD-URBPH) and spray-dried (SD-URBPH) at different inlet air temperatures of 100–160 °C. The water solubility and antioxidant activity of FD-URBPH were higher than those of SD-URBPH. Nevertheless, encapsulation of hydrolysate with 10% cluster dextrin and an inlet temperature of 120 °C was also successful in maintaining protein qualities, which showed high 2,2′-azino-bis 3-ethylbenzthiazoline-6-sulfonic (ABTS•+) scavenging activity (89.14%) and water solubility index (92.49%) and low water activity (aw = 0.53). Moreover, encapsulation preserved the antioxidant activity of peptides during gastrointestinal digestion better than the free form. URBPH and its spray-dried microcapsules could be used as bioactive ingredients in functional drinks or foods.

Rheological, textural properties and storage stability of mayonnaise formulated with protein hydrolysate derived from yellow mealworm (Tenebrio molitor)

Abstract Yellow mealworm (Tenebrio molitor), the larva stage of darkling beetle, confers high nutritional and functional protein and it can serve as a sustainable protein source. The present study therefore evaluated the effect of replacing the egg yolk as emulsifier with yellow mealworm protein hydrolysate powder (YMPH) (0-100%) at 20% increment levels on the rheological and textural properties, colour attributes, emulsion microstructure and storage stability of mayonnaise. The emulsion stability results demonstrated that mayonnaise with up to 60% substitution of YMPH displayed excellent storage stability for 3 weeks (&lt;2% phase separation). In terms of textural properties, all samples showed no significant difference () in firmness whereas consistency decreased steadily with increasing YMPH concentration levels. Microstructure observation of all mayonnaise formulations demonstrated a gradual increase in oil droplet size in parallel with the increase in YMPH concentration. For rheological properties, all mayonnaise exhibited similar gel-like behaviour with greater storage modulus (G’) than loss modulus (G”) and loss tangent (tan δ) less than 1.0. For the colour attributes, increasing YMPH level led to significant decrease () in the L* and b* factors from 73.0 to 27.2 and 23.9 to 8.1, respectively. However, the overall a* factor value increased significantly () from 1.11 to 5.10 as the YMPH concentration increased. This study revealed that insect-based protein hydrolysate has a good potential to serve as an emulsifier.

Development of a Ready-to-Eat Fish Product Enriched with Fish Oil Entrapped in a κ-Carrageenan Egg White Fish Protein Hydrolysate Dry Powder.

This work describes the development of a ready-to-eat (RTE) product based on an equal mixture of fish mince from three undervalued fish species with different fat contents and protein gelling capacity, which was enriched with fish oil entrapped in a κ-carrageenan egg white fish protein hydrolysate powder, obtained by either spray drying (SD) or heat drying (HD) at 80 °C (HD80). Previously, the spray-dried (SD) powder and heat-dried powders obtained at 45 °C, 60 °C and 80 °C (HD45, HD60 and HD80) were characterised in terms of water solubility, lipid oxidation (TBARS), hygroscopicity and ζ potential. All HD powders showed higher hygroscopicity and lower TBARS than the SD powder. The dry powder was incorporated into a blend composed of salt-ground batter and raw mince to improve binding and textural properties. Changes in water-holding capacity, colour, shear strength and microorganisms were monitored during the processing steps. The RTE product presented a high protein content and a noticeable amount of long-chain ω-3 fatty acids. The use of undervalued fish species together with fish oil and a protein hydrolysate from fish waste contribute to improving the sustainability of fishery resources, being conducive to obtaining a potentially functional RTE product.

Production of functional spent hen protein hydrolysate powder and its fortification in food supplements: A waste to health strategy

Spent hens are discarded from the poultry industry as they lose their ability to lay eggs and are rendered unsuitable for consumption due to poor meat quality. This work provides a strategy to utilize spent hen meat by developing protein hydrolysates with enhanced antioxidative properties for developing functional protein supplement which was previously unexplored. Spent hen meat was hydrolysed using two proteases (alcalase and flavourzyme) followed by drying (spray and freeze drying). Hydrolysate powders thus generated were further characterized for their physico-chemical and functional attributes. Particle size and morphology were more prominently affected by drying method while the functional properties were influenced by the enzyme type. The solubility, antioxidant activity and bioaccessibility of spray dried spent hen hydrolysate powder developed using flavourzyme (SD-SPHF) was found superior to those developed using alcalase. Hydrophobic amino acids with rich antioxidant activity were also found to be higher in SD-SPHF. Considering higher functionality of SD-SPHF, it was incorporated @10% in whey protein supplement and was found to be acceptable from a sensory viewpoint. The study highlights that spent hen protein hydrolysate powders can be effectively utilized for the development of economic functional food supplements after suitable biotechnological interventions.

Antioxidant Activity of Cocoa Flavored Sterilized Milk Fortified with Whey Protein Hydrolysate Derived from Gastrointestinal Proteinases Digestion

The objectives of this work were to study the change in α-amino content and antioxidant activity of whey protein hydrolysate (WPH) using gastrointestinal proteinases (pepsin and pancreatin). In addition, whey protein hydrolysate powder (WPHP) with high antioxidant activity were produced by simulated GI digestion using an in vitro pepsin - pancreatin hydrolysis for supplementation in flavored milk. Whey protein was hydrolyzed with pepsin for 2 h followed by pancreatin for 3 h. WPH was collected to determine the α-amino content and antioxidant activity. The results showed that digested WPH contained higher α-amino content and antioxidant activity than undigested whey. To study optimum temperature, WPH was dried using Spray Dryer at 130, 140, and 150 °C. Results showed that WPHP at 150 °C exhibited the highest antioxidant activity with a major area peak of molecular weight around &gt;12,000 - 990 Da (43.4 %) and 990 - 336 Da (23.7 %). WPHP at 150 °C was selected to supplement in Cocoa flavored sterilized milk (CFSM_WPHP). α-Amino content, antioxidant activity, and microbiological of CFSM_WPHP were investigated. CFSM_WPHP contained higher α-amino content and antioxidant activity than Control (without addition of WPHP). Total plate count, fecal coliform, and E. coli of CFSM_WPHP were under Notification of the Ministry of Public Health of Flavored milk. These results suggested that WPHP has the potential as nutritive and antioxidative supplementation for Cocoa flavored sterilized milk.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Whey protein hydrolysate prepared by pepsin-pancreatin had antioxidant activity&#x0D; At 150 ºC was the optimum drying temperature to produce WPH powder&#x0D; WPH exhibited the molecular weight around &gt;12,000-990 Da and 990 - 336 Da&#x0D; Addition of WPH improved antioxidant activity of Cocoa flavored sterilized milk&#x0D; WPH powder exhibited the potential of being used as a functional peptide&#x0D; &#x0D; GRAPHICAL ABSTRACT

Preparation of a protein drink from fish protein hydrolysate obtained from tilapia skin waste

This study investigated the extraction of protein hydrolysate from tilapia skin waste and its utilisation for the preparation of a protein drink. Tilapia skin was first prepared by removing lipids using 95% ethanol. Protein hydrolysate was then extracted using 0.375% papain at 40°C for 120 mins. The physicochemical properties of the protein hydrolysate were analysed and were then used to prepare a protein drink. The analysis of shelf-life and the prediction of shelf-life of products using the accelerated shelf-life testing method (Q10) were carried out. The content of protein hydrolysate powder in tilapia skin was 29.68±1.32 (g/100 g). Sensory analysis results showed that the protein beverage received an overall liking score of 7.13±1.27 from the sensory panel. Based on the Q10 calculations, the product shelf-life at the recommended temperature of 4°C with a safety factor of 10% was 12 days. According to the Thai FDA for pasteurised beverage regulation no. 195, the product complied with the Thai FDA standard guidelines. These results suggested that the fish protein hydrolysate obtained from tilapia skin waste is a rich resource of protein and is suitable for producing value-added fish skin protein drinks.

Effect of milk-derived bioactive peptides on the lipid stability and functional properties of beef nuggets

The present study was conducted to ascertain the beneficial effects of bioactive peptides on the oxidative stability and functional properties of beef nuggets. In this study, milk casein protein hydrolysates were extracted and incorporated into beef nuggets which were then subjected to different assessment parameters including oxidative stability, functional capability as well as microbial and physico-chemical quality tests were performed for determining the meat quality at different storage periods. The casein protein hydrolysate powder (CPH) was added at different concentrations in nuggets CPH 2%, 4%, 6% and 8%, with reference to storage period of 0, 5, 10 and 15 days at 4 °C. The results regarding total phenolic contents (TPC) and DPPH free radical scavenging assay showed a significant increased with respect to CPH powder and significantly decreased with respect to storage interval. The TVBN, TBARS and POV of the CPH powder incorporated raw beef nuggets also differed significantly within groups with storage time. Higher POV and TBARS were noticed in the CPH 8% incorporated beef nuggets. However, the raw beef nuggets that were made by the incorporation 8% CPH powder, maintained significantly lower level of TBARS at the end of the storage period in contrast with the levels of the control (CPH 0%). The results of the pH and Hunter color test also showed a significant difference with respect to different groups. The microbiological analysis of beef nuggets showed a significant decrease in the level of both the total aerobic and coliform counts and also indicated a decreasing trend in the level of contamination by these bacteria within the groups. This depicted that the casein protein hydrolysate powder (CPH) or simply, the peptide powder has the strong ability to decrease lipid oxidation and related shelf-life retarding natural processes occurring in the meat. It can also greatly enhance the functional properties of the raw meat (beef) and meat products. Thus, it is seen that the bioactive peptides (BAP’s) are a key factor in improving the oxidative stability and functional properties of beef nuggets.

Functional and morphological characterization of undersized crawfish minced meat hydrolysate powders produced with alkaline protease and bacterial protease

Undersized crawfish meat protein may be enzymatically hydrolyzed to produce protein hydrolysate powders with functional properties. The objective of the study was to evaluate the functional and morphological characterization of undersized crawfish minced meat hydrolysate powders produced with alkaline protease and bacterial protease. The degree of hydrolysis vs. time was determined and hydrolyzation times chosen. Alkaline and bacterial protease enzymes were added to the crawfish minced meat at 3% w/w and hydrolyzed for 0.5, 3, and 7 h. After hydrolysis, the enzymes were inactivated, and the hydrolysates were spray dried at 150 °C. Molecular weight, morphology, minerals, amino acid profile, color and functional properties including antioxidant activity, emulsification stability, water absorption, and fat absorption capacity were evaluated for the spray dried hydrolysate powders. Triplicate experiments were conducted, and the data was statistically analyzed (P < 0.05). All the powders had 5 and 2 kDa molecular weight bands. Functional properties of hydrolysate powders were affected by enzyme type and reaction time, which indicated that the enzymes promote the production of different peptides that could be responsible for differences in the functional properties of the hydrolysate powders. The morphology of CPH powders showed round and smooth and irregularly spherical shape particles with dents.

Development of a spray-dried conjugated whey protein hydrolysate powder with entrapped probiotics

Bifidobacterium animalis ssp. lactis ATCC27536 and Lactobacillus acidophilus ATCC4356 were encapsulated in a conjugated whey protein hydrolysate (WPH10) through spray drying. Probiotic cultures were added at the ratio of 1:1 into the conjugated WPH10 solution at a spiking level of about 10 log10 cfu/mL. The mixture was spray dried in a Niro drier with inlet and outlet temperatures of 200°C and 90°C, respectively. The final dried product was determined for cell viability and further stored for 16 wk at 25°, 4°, and -18°C to monitor viability and functionality. Micro images showed the presence of link bridges in non-conjugated WPH10, whereas, in the case of conjugated WPH10, round particles with pores were observed. The mean probiotic counts before and after spray drying were 10.59 log10 cfu/mL and 8.98 log10 cfu/g, respectively, indicating good retention of viability after spray drying. The solubility and wetting time of the WPH10-maltodextrin (MD) encapsulated probiotic powder were 91.03% and 47 min, whereas for WPH10, the solubility and wetting time were 82.03% and 53 min, respectively. At the end of storage period, the counts were 7.18 log10 cfu/g at 4°C and 7.87 log10 cfu/g at -18°C, whereas at 25°C the counts were significantly reduced, to 3.97 log10 cfu/g. The solubility of WPH-MD powder was 82.36%, 83.1%, and 81.19% at -18°C, 4°C, and 25°C, respectively, and wetting times were 61 min, 60 min, and 63 min at -18°C, 4°C, and 25°C, respectively. By contrast, for WPH10 powder, the solubility significantly reduced to 69.41%, 69.97%, and 68.99% at -18°C, 4°C, and 25°C, and wetting times increased to 71 min, 70 min, and 72 min at -18°C, 4°C, and 25°C, respectively. The conjugated WPH10 is thus demonstrated as a promising carrier for probiotics and can be further used as an ingredient for developing functional foods, to harness their enhanced functionality and health benefits derived from both WPH and probiotics.

Optimization of enzymatic protein hydrolysis conditions of Asiatic hard clam (Meretrix meretrix)

This study was aimed to optimise the Alcalase® enzymatic hydrolysis extraction of Asiatic hard clam (AHC) (Meretrix meretrix) protein hydrolysate in terms of hydrolysis time, hydrolysis temperature, hydrolysis pH, and concentration of enzyme. Protein hydrolysate produced from AHC (M. meretrix) meat was used to determine the optimum hydrolysis conditions. Hydrolysis of AHC meat was optimised using the Central Composite Design Response Surface Methodology (RSM) (CCD). The relationship between four parameters such as temperature (45 – 65°C), enzyme to substrate concentration (1 – 2%), hydrolysis time (60 – 180 mins), and pH (7.5 – 9.5) to the degree of hydrolysis was investigated. The optimum conditions for enzymatic hydrolysis of AHC meat to achieve the maximum degree of hydrolysis (DH) were observed at 65°C, enzyme to substrate concentration of 1%, hydrolysis time of 60 mins, and pH 7.5. The enzymatic protein hydrolysis of AHC meat was predicted using a two factors interaction (2FI) model. Under these optimum conditions, DH's predicted value was 97.41%, which was close to the experimental value (97.89%). The freeze-dried protein hydrolysate powder was characterized concerning the proximate composition. Proximate analysis revealed that the AHC meat contains 7.92±1.76% of moisture, 2.23±0.89% of crude fat, 1.98±0.82 of ash, and 10.53±0.04% of crude protein. While the Asiatic hard clam protein hydrolysate (AHCPH) composed 9.12±0.02% of moisture, 0.80±0.29% of crude fat, and 27.76±0.10% of ash. The protein hydrolysate produced also contained high protein content (50.09±0.88%) and may serve as a good protein source.

Hydrolysis products from sockeye (Oncorhynchus nerka L.) heads from the Kamchatka Peninsula produced by different methods: biological value

Introduction. Sockeye salmon (Oncorhynchus nerka L.) is a valuable Pacific salmon. Sockeye heads are a significant share in processing sockeye salmon. Traditionally, fish by-products are used to make fishmeal. However, due to the high content of collagen proteins and fat in sockeye salmon heads, it is difficult to produce fishmeal from this raw material. Controlled enzymatic or combined hydrolysis allows protein, fat, and minerals to be extracted to supply the market with higher value products with desirable features. This research was aimed to analyse the chemical composition and biological value of hydrolysis products obtained from sockeye heads.&#x0D; Study objects and methods. We investigated hydrolysis products of sockeye salmon heads, namely protein hydrolysates, fat and sludge. Thermal hydrolysis and enzymatic-thermal hydrolysis were used for the tests. Thermal hydrolysis was realized in reactor. For enzymatic-thermal hydrolysis, the raw material was pre-treated by proteolytic enzyme Alcalase. The hydrolysates obtained were investigated. Chemical composition was determined in accordance with State Standard 7636-85. HPLC was used for molecular weight and amino acid analysis. Gas chromatography was used for fatty acid analysis. Biological value of proteins was determined by the balance of the amino acid composition comparing it with the “ideal protein model”.&#x0D; Results and discussion. Thermal hydrolysis resulted in the production of protein hydrolysate powder with protein content of 92.0% dry matter and a protein recovery rate of 39.6%. Combined hydrolysis resulted in the production of protein hydrolysate powder with protein content of 92.6% and a protein recovery rate of 83%. All protein hydrolysates contained all essential amino acids. The biological value of protein hydrolysate obtained by thermal and combined hydrolysis was 80.1 and 82.8%, respectively.&#x0D; Conclusion. Hydrolysed products obtained by thermal and enzymatic-thermal hydrolysis had a valuable chemical composition and could be recommended for food and feed use.

An investigation into copper-binding capacity of the white leg shrimp head (Litopenaeus vannamei) protein hydrolysate

The aim of this study is to obtain the copper-binding protein hydrolysate from the white leg shrimp head (WLSH) by-product using enzymatic hydrolysis. The outcome indicated that the copper-binding capacity (CBC) of the WLSH protein hydrolysate achieved the maximum value of 19.4±0.5 mg Cu2+/g protein with hydrolysis conditions including Flavourzyme preparation, pH 7.5, 50°C, the enzyme:substrate (E:S) ratio of 80 U/g protein and 5h of hydrolysis. Under the pH treatment in a range of 1-11 or heat treatment at 100°C for up to 180 min, its CBC remained over 80%. The water holding capacity (WHC) and the oil-holding capacity (OHC) of the protein hydrolysate were 4.1±0.1 ml water/g protein hydrolysate powder and 4.5±0.1 ml oil/g protein hydrolysate powder, respectively. The solution also encompassed up to 8 essential amino acids, accounting for 36.1% of the total amino acid content. The protein hydrolysate could serve not only as a copper chelating agent, preventing copper-deficient or superfluous relating diseases, but also as a texturizer and an amino acid supplement fortified in various types of food.

Chemical composition and major volatile compounds of the hydrolyzed product from &lt;i&gt;Kappaphycus alvarezii&lt;/i&gt; by-products using flavourzyme

The chemical composition of flavourzyme hydrolysis product from Kappaphycus alvarezii by-products was analyzed. The results showed that the protein hydrolysate powder had high content of proteins (21.66%) and low content of lipids (0.22%). Hydrolyzed products contained about 15 free amino acids with relatively high content of some amino acids such as aspartic acid (1,879 mg/100 g), glutamic acid (1,813 mg/100 g), glycine (1,121 mg/100 g), tyrosine (1,203 mg/100 g) ) and serine (3,165 mg/100 g). In addition, main volatile flavor compounds such as acetophenone; nonanal; indole; 2.4-di-tert-butylphenol; heptadecane; 6.10.14- trimethylpentadecan-2-one have also been discovered. As a result, the by-products of K. alvarezii take a potential role in the food industry.

Evaluation of physicochemical and functional properties of spray-dried protein hydrolysate from non-penaeid shrimp (Acetes indicus).

Protein hydrolysate powder was prepared from non-penaeid shrimp (Acetes indicus) by enzymatic hydrolysis using Alcalase enzyme. Extraction conditions such as pH (6.5, 7.5 and 8.5), enzyme to substrate ratio (1.0, 1.5 and 2.0) and temperature (40, 50 and 60 °C) were optimized against the degree of hydrolysis using response surface methodology. Protein hydrolysate comprised of 740 g kg-1 protein, 150 g kg-1 ash and 90 g kg-1 fat contents. The amino acid score showed superior attributes with 56% essential amino acids. Furthermore, the functional properties of spray-dried protein hydrolysates were evaluated. Protein solubility was found to be the 90.20% at pH 2 and 96.92% at pH 12. Emulsifying properties were found to vary with the concentration of protein hydrolysates and the highest emulsifying capacity (26.67%) and emulsion stability (23.33%) were found at a concentration of 20 mg mL-1 . The highest and the lowest foaming capacity were observed at pH 6 and pH 10 with a concentration of 20 mg mL-1 . The water holding capacity of protein hydrolysate was found to increase with concentration, with a value of 5.4 mL g-1 at a concentration of 20 mg mL-1 . The results of the present study indicate that the use of A. indicus for the production of protein hydrolysate has good functional properties and nutritional value, rendering it suitable for broad industrial food applications. © 2019 Society of Chemical Industry.

Whole wheat cracker fortified with biocalcium and protein hydrolysate powders from salmon frame: characteristics and nutritional value

Abstract Objectives This study aimed to develop whole wheat crackers fortified with biocalcium (BC) and protein hydrolysate (PH) powders from salmon frame at varying substitution levels. Materials and Methods Whole wheat cracker fortified with BC and protein hydrolysate PH powders from salmon frame was produced. BC and PH powders or their mixtures at different ratios (3:1, 1:1, 1:3) were used to fortify the dough mix at a substitution level of 16.67% based on the whole wheat flour content. The physical, textural, sensory, and nutritional profiles of the crackers produced were examined and compared with crackers without fortification. Results The weight, colour, textural properties, and thickness of the crackers varied with the addition of different ratios of BC and PH powders. The incorporation of BC/PH at ratio (3:1) showed no negative effect on sensory properties. The crackers thus produced possessed higher protein, fat, calcium, phosphorus, sodium, and cholesterol but lower carbohydrate, sugar, fibre, and energy value than the control crackers without fortification. The crackers contained 0.026–0.045 mg/100 g polyunsaturated fatty acid. Developed crackers had a denser structure and were less porous than the control crackers as shown in scanning electron microscopic images. In scanning electron microscopy-energy dispersive X-ray spectroscopic (SEM-EDX) analysis, the crackers fortified with BC/PH at ratio (3:1) had higher calcium and phosphorus contents and intensity than the control. Conclusions This study demonstrated that the addition of BC and PH powders obtained from salmon frame represent a promising means of increasing the nutritive values of crackers.

An integrated strategy for the effective production of bristle protein hydrolysate by the keratinolytic filamentous bacterium Amycolatopsis keratiniphila D2

In a conventional microorganism-mediated biological process for degradation of keratinous waste material the production of keratin-specific proteases (i.e., keratinases) and the hydrolysis of keratin-rich residual biomass both take place during the same stage of the bioprocess and, as a consequence, occur simultaneously under suboptimal conditions. In the present study the keratinolytic actinomycete Amycolatopsis keratiniphila D2 was successfully employed to biodegrade thermally pretreated porcine bristles at high solids loading (16% w/v) via a novel cultivation methodology. Indeed, the two-stage submerged fermentation process developed in this work enabled to efficiently recover, in a single unit operation, about 73% of the protein material contained in the keratinous biowaste structure, resulting in an overall accumulation of 89.3 g·L−1 protein-rich hydrolysate and a productivity of 427 mg crude soluble proteins per litre per hour. The obtained protein hydrolysate powder displayed a 2.2-fold increase in its in vitro pepsin digestibility (95%) with respect to the non-hydrolysed pretreated substrate (43%). In addition, the chromatogram obtained by size-exclusion chromatography analysis of the final product indicated that, among the identified fractions, those consisting of small peptides and free amino acids were the most abundantly present inside the analysed sample. Given these facts it is possible to conclude that the soluble proteins, peptides and free amino acids recovered through the newly designed two-stage bioextraction process could represent a viable alternative source of protein in animal feed formulation.

Chemical, physical, rheological and sensory properties of biscuit fortified with protein hydrolysate from cephalothorax of Pacific white shrimp.

Chemical, physical, rheological and sensory properties of biscuits fortified with shrimp protein hydrolysate powder (SHP) at various levels (0-7.5%, flour substitution) were investigated. The addition of 7.5% SHP slightly decreased diameter of biscuit and thickness was decreased as SHP at levels of 2.5-7.5% was incorporated. Hardness and fracturability of biscuit decreased as the levels of SHP was higher than 1.25 and 2.5%, respectively. Surface of biscuit became more reddish and yellowish as SHP was added. The addition of 5% SHP increased likeness score of resulting biscuit. Fortification of SHP affected the viscoelastic properties of dough. Deformation resistance and strength of dough decreased with increasing levels of SHP. Additional volatile compounds including aldehyde, ketone, alkane and ether, were detected when 5% SHP was incorporated, thus more likely contributing to odor and flavor of resulting biscuit. The addition of 5% SHP into biscuit resulted in the increased protein content with reduction of carbohydrate. Therefore, the biscuit could be fortified with 5% SHP and had higher nutritional value and increased sensory properties.

Ovarian development in Bactrocera cucurbitae Coquillett as influenced by diet

To enable mass rearing of the melon fly, Bactrocera cucurbitae Coquillett, a study was undertaken to evaluate dietary constituents comprising of honey, water, protein hydrolysate and yeast powder. Different diets were prepared consisting of protein hydrolysate (1 g, 3 g, 5 g, and 7 g) and yeast powder (5 g, 10 g, 15 g, and 20 g) mixed in 5 ml honey and water 100 ml. Of these, the two diets viz., protein hydrolysate 7 g + honey 5 ml + water 100 ml and yeast powder (10 g + honey 5 ml + water 100 ml) were found equally effective in terms of ovary development and ovarian index, when dissected at 5th, 10th, 15th and 20th day after adult eclosion. In case of protein hydrolysate 7 g, the ovarian index was 0.38 mm2, 1.75 mm2, 3.57 mm2, and 4.04 mm2 at 5th, 10th, 15th and 20th day, respectively and in case of yeast powder 10 g the ovarian index was 0.39 mm2, 1.77 mm2, 3.63 mm2, and 4.10 mm2 at 5th, 10th, 15th and 20th day, respectively, after adult eclosion. In both the treatments, the ovary length and breadth were also significantly more in comparison to other treatments, consisting of different quantities of protein source. Thus, the diets containing 7 g protein hydrolysate and 10 g yeast powder were the most suitable diets for mass rearing of B. cucurbitae.

Comparative analysis of functionality of spray dried whey protein hydrolysates obtained by enzymatic and microbial hydrolysis

The aim of this study was to examine the bioactive potential of hydrolysate powders produced by enzymatic and microbial hydrolysis of whey proteins followed by spray drying, in order to reveal which one of these processes result in a product with significantly improved functional properties. Hydrolysate powders produced by the two different biotechnological processes were compared based on their antioxidant (DPPH and FTC), antibacterial as well as erythrocyte membrane stabilizing activities. The performed tests revealed that the concentration of at least 178.4 mg mL-1 of the whey protein hydrolysate powder, produced by tryptic digestion, could inhibit the process of lipid peroxidation by 50 %, suppress the microbial contamination caused by S. aureus ATCC25923, B. cereus ATCC 11778 and L. monocytogenes, and provide the antioxidant and membrane stabilizing activities greater than 50 %. On the other hand, the hydrolysate powder obtained by whey fermentation at the concentration of at least 811.5 mg mL-1 achieved 50 % of all tested bioactivities, with the emphasis on the significantly more pronounced antibacterial activity against all tested strains. In that sense, tryptic hydrolysis could be highlighted as an optimal process that provides production of the whey hydrolysate with pronounced bioactive properties that could be considered as a very promising natural food supplement.