DETERMINATION OF HEN EGGSHELL STRENGTH BY THE PUNCTURE METHOD

The aim of this study was to design and apply the measuring acquisition system, or a device for determining the limit values of eggshell strength using the puncture method. This study focused on class "M" eggs produced on a laying hen farm in the vicinity of Čаčak, and determined the external physical properties of egg quality: length, width, shape index and weight. In addition, the following eggshell properties were determined: weight, proportion, thickness, and puncture force. Average egg length was 58.05 mm, width 45.46 mm, and shape index 78.25. Average egg weight was 65.89 g, and the eggshell ratio 12.76% (8.44 g). Average eggshell thickness was 0.48 mm with a 4.69% coefficient of variation. Results showed that the tested eggs had uniform strength, with average value of the minimum shell puncture force 26.34 N, with a 0.95% coefficient of variation.

Fortification of Maize Tortilla with an Optimized Chickpea Hydrolysate and Its Effect on DPPIV Inhibition Capacity and Physicochemical Characteristics

Chickpea hydrolysates have shown bioactivity towards type 2 diabetes by inhibiting dipeptidyl peptidase (DPPIV) activity. The objective was to compare the effect of adding different levels of an optimized bromelain hydrolysate from chickpea isolated protein on DPPIV inhibition capacity and physicochemical properties of maize tortilla. White and blue maize tortillas, with no added chickpea hydrolysates were compared with fortified tortillas at the levels of 5%, 10%, and 15% w/w. Changes in color (L* a* b*, hue angle, and ΔE), texture (hardness, cohesiveness, and puncture force), and moisture were tested. Soluble protein determination and SDS-PAGE electrophoresis were used to characterize the protein profiles, and LC-MS-MS was used to sequence the peptides. DPPIV inhibition was evaluated before and after simulated gastrointestinal digestion. Peptides in the hydrolysates had high hydrophobicity (7.97–27.05 kcal * mol −1) and pI (5.18–11.13). Molecular docking of peptides showed interaction with DPPIV with an energy of affinity of –5.8 kcal/mol for FDLPAL in comparison with vildagliptin (−6.2 kcal/mol). The lowest fortification level increased soluble protein in 105% (8 g/100 g tortilla). DPPIV inhibition of white maize tortilla increased from 11% (fresh control) to 91% (15% fortification), and for blue tortilla from 26% to 95%. After simulated digestion, there was not a difference between blue or maize tortillas for DPPIV inhibition. Fortification of maize tortilla with chickpea hydrolysate inhibits DPPIV and can potentially be used in the prevention and management of type 2 diabetes. However, due to observed physicochemical changes of the fortified tortilla, sensory properties and consumer acceptance need to be evaluated.

Physiological and environmental control of seed germination timing in Mediterranean mountain populations of Gundelia tournefortii

Fruit and seed morphology interact with embryo physiology and environmental conditions to control seed germination timing. This interaction plays a pivotal role in ecosystems with narrow windows for seedling establishment, such as the Mediterranean mountains. In this study, we investigated the germination responses of the secondary capitula (disseminules) of Gundelia tournefortii from East Mediterranean mountain populations. When incubated at 15 °C, intact capitula did not reach 20% of final germination, with or without the addition in the germination substrate of GA3 (250 mg L−1), while extracted fruits reached 50% of germination, which increased to ca. 70% when treated with GA3. Cold stratification enhanced final germination of the capitula at 15 °C to ca. 65%, although almost half of the initially sown capitula germinated during the second month of stratification at 5 °C. During the stratification at 5 °C, peak puncture force needed to pierce the basal part of the capitula decreased linearly and capitula started germinating after one month, which corresponded to a peak puncture force of 0.41–0.35 N. These findings highlight the presence of mechanical and hormonal components of physiological seed dormancy. The morphology of the disseminules controls seed germination timing, by interacting with cold winter temperatures and starting seed germination only in early winter. These findings not only provide new insights on the reproduction from seeds of this plant, but by highlighting high germination of cold-stratified intact capitula, can also support plant propagation programmes for this key wild edible species, very important for food security and the livelihoods of local communities in the East Mediterranean region.

Predator–Prey Interactions Examined Using Lionfish Spine Puncture Performance

Synopsis Puncture mechanics can be studied in the context of predator–prey interactions and provide bioinspiration for puncture tools and puncture-resistant materials. Lionfish have a passive puncture system where venomous spines (dorsal, anal, and pelvic), the tool, may embed into a predator’s skin, the target material, during an encounter. To examine predator–prey interactions, we quantified the puncture performance of red lionfish, Pterois volitans, spines in buccal skin from two potential predators and porcine skin, a biological model for human skin. We punctured dorsal, anal, and pelvic lionfish spines into three regions of buccal skin from the black grouper (Mycteroperca bonaci) and the blacktip shark (Carcharhinus limbatus), and we examined spine macro-damage (visible without a microscope) post puncture. Lionfish spines were more effective, based on lower forces measured and less damage incurred, at puncturing buccal skin of groupers compared to sharks. Anal and dorsal spines incurred the most macro-damage during successful fish skin puncture trials, while pelvic spines did not incur any macro-damage. Lionfish spines were not damaged during porcine skin testing. Anal spines required the highest forces, while pelvic spines required intermediate forces to puncture fish skin. Dorsal spines required the lowest forces to puncture fish skins, but often incurred macro-damage of bent tips. All spine regions required similar forces to puncture porcine skin. These data suggest that lionfish spines may be more effective at puncturing humans such as divers than potential fish predators. These results emphasize that puncture performance is ultimately determined by both the puncture tool and target material choice. Lionfish puncture performance varies among spine region, when taking into account both the puncture force and damage sustained by the spine.

Direct methods for determination of the egg shell strength

During the manipulation of hen eggs from the farm to the consumer due to action of external forces and weak mechanical strength of shell, the eggs break. The goal of egg producers is to reduce losses when breaking eggs during the production and placement, and thus increase revenues. Each egg can be damaged by external forces whose values are greater than maximum strength of the egg shell. Direct and indirect methods are used to determine the quality of eggs and shell strength. By direct methods, strength of the shell can be determined on the basis of puncture force measurements, impact forces, quasi-static compression forces and free fall forces on a known surface. In our research, a device was constructed for the realization of experiment and a direct method for determining strength of eggs was applied on the basis of measured breaking force of the shell. The device for measuring strength of eggs by the direct method of puncture eggshell was constructed and applied at the Faculty of Technical Sciences and the Faculty of Agronomy in Čačak. Class "M" hen eggs produced on the "Grbović" farm in the vicinity of Čačak were used in the research. The laying hens are a 41-week-old Isa Brown hybrid. During the research, physical characteristics of hen eggs were determined: length, width, index of shape and weight of eggs, as well as weight of the shell, share of the shell in the total mass of eggs, thickness and puncture force of the shell. The results of research show that the length of egg is 57.00 mm, width 44.59 mm with a coefficient of variation from 2.7 to 1.4%. The thickness of egg shell is on average 0.39 mm, in range from 0.377 to 0.416 mm. The share of shell is 10.54% of average weight of eggs (62.43 g). The quality of the tested eggs was quite uniform because the puncture force of egg shell ranged from 20.35 to 23.97 N. The research results are important for cage construction, design of egg collection equipment, design of egg packaging, and applicable in selection for obtaining new genotypes of laying hens with increased resistance to egg breaking.

Effect of glycerol concentration on physical and texture properties of edible films prepared from karaya gum

This study formulated edible films based on karaya gum in the presence of glycerol. Physical properties of films were investigated by various methods including texture analysis and differential scanning calorimeter (DSC). The obtained results revealed that glycerol acted as a plasticizer contributing to improve the flexibility, water vapor permeability and heat resistance of karaya films. The best value of tensile strength and puncture force for edible films could be achieved by the combination of karaya gum and glycerol at the concentrations of 4% (w/v) and 10% (w/w), respectively.

Experimental study of the optimum puncture pattern of robot-assisted needle insertion into hyperelastic materials

The robot-assisted insertion surgery plays a crucial role in biopsy and therapy. This study focuses on determining the optimum puncture pattern for robot-assisted insertion, aiming at the matching problem of needle insertion parameters, thereby to reduce the pain for patients and to improve the reachability to the lesion point. First, a 6-degrees of freedom (DOFs) Computed Tomography (CT)-guided surgical robotic system for minimally invasive percutaneous lung is developed and used to perform puncture experiments. The effects of four main insertion factors on the robotic puncture are verified by designing the orthogonal test, where the inserting object is the artificial skin-like specimen with high transparent property and a digital image processing method is used to analyze the needle tip deflection. Next, the various phases of puncture process are divided and analyzed in detail in view of the tissue deformation and puncture force. Then, short discussion on the comparison of puncture force with different effect factors for the same beveled needle is presented. The same pattern can be observed for all of the cases. Finally, based on the experimental data, the formulations of the puncture force and needle deflection which depends on Gauge size, insertion velocity, insertion angle, and insertion depth are developed using the multiple regression method, which can be used to get an optimum puncture pattern under the constrains of minimum peak force and minimum needle tip deflection. The developed models have the effectiveness and applicability on determining the optimum puncture pattern for one puncture event, and which can also provide insights useful for the setting of insertion parameters in clinical practice.

Investigation of vibration parameters for needle insertion force reduction

Many medical interventions in therapy and diagnostics require needle insertion into tissue. Common complications such as increased pain and formation of haematoma are caused by wrong needle positioning. It has been shown that pain experience and needle positioning can be improved by a reduction of insertion force, which can be achieved by vibrating the needle axially. An experimental setup has been designed to investigate the influences of different combinations of vibration frequencies (10, 100, and 200 Hz) and vibration amplitudes (20, 100, and 500 μm) during needle insertion into thin sheets of polyethylene terephthalate (PET). A customary 20 W loudspeaker was used to generate the vibration. The results indicate a maximum reduction of 73 % in puncture force and up to a 100 % reduction in shaft friction force. However, the additional vibration force generated by the vibration movement has to be high enough to generate positive effects in terms of force reduction.

Development of milk protein edible films incorporated with Lactobacillus rhamnosus GG

Bioactive edible films have the potential to be probiotic carriers. This innovative approach can replace plastic packaging and can benefit human health. This study demonstrated the incorporation of Lactobacillus rhamnosus GG (LGG) into whey protein isolate (WPI) and sodium caseinate (NaCas) edible films. Probiotic cells were directly incorporated into the film forming solutions, and the films were produced by the casting method. The physical, mechanical, and probiotic viability properties of the edible films were determined in the presence and absence of LGG. Furthermore, the viability of LGG was evaluated during the drying process and storage of 14 days at 4 °C and 25 °C, respectively. The results showed the incorporation of LGG increased the moisture content, puncture force, and lightness of both films. However, viability of LGG was lower in the WPI film regardless of storage temperature. At the end of storage days, both WPI and NaCas edible films maintained the LGG viability above the recommended levels when stored at 4 °C, which was 106 CFU/g. The findings of this study suggested that edible films made of WPI and NaCas showed feasibility to immobilize LGG with chilled storage at 4 ℃.

Investigation on the microstructural characteristics and quasi-static puncture resistance of both domesticated and wild silkworm cocoons

The very thin and lightweight silkworm cocoon has outstanding mechanical properties attributed to its specific composite microstructure. However, the microstructures of the cocoons have not been studied quantitatively, and their anti-puncture performance has not been examined as well. In this study, both domesticated ( Bombyx mori) and wild silkworm cocoons ( Antheraea pernyi, Antheraea mylitta and Samia canningi) were investigated for their microstructures using fractal theory, and their quasi-static puncture resistance was tested and compared. In addition, the effects of cocoon layers and hot-press treatments on the puncture resistance of two cocoon types ( B. mori and A. pernyi) were investigated. The three wild cocoons demonstrated significantly higher fractal dimensions, higher fiber intersectional densities and low porosities, indicating their structures are more optimized. They also displayed better puncture resistance than B. mori. Increased layer numbers could significantly increase the puncture resistance of both cocoon types and A. pernyi showed more remarkable increases. Moreover, the two cocoon types showed optimum puncture resistance after heat treatment with hot-press temperature of 135℃ and pressure of 25 MPa, and A. pernyi showed better puncture resistance after such treatment. Finally, both the maximum puncture force and puncture energy of cocoons displayed a linear increase with the increasing fractal dimensions. The new insights can guide the development of novel protective fiber composites with desirable and predictable anti-puncture performance.