Physicochemical properties of starch of four varieties of native potatoes.

The limited industrial use of indigenous varieties of native potatoes has caused a decrease in its cultivation, restricting it to the self-consumption of the Andean population. The present study analyzed the physicochemical, thermal, and structural properties of the starches extracted from four of these varieties Aq'hu Pukucho, Yurakk Kkachun Wakkachi, Yurac Anca, and Huarmi Mallco, as a potential source of be used in industries such as food, pharmaceutical and, bioplastics. The percentage yield in wet extraction ranged between 14.53 and 20.26 %. The luminosity L* and whiteness index (WI) values were observed in ranges of 90.75-92.71 and 90.05-91.50, respectively. The Finding revealed various techno-functional properties, since the level of amylose varied between 36.29 and 43.97 %, an average zeta potential of -22 mV, and a maximum viscosity between 19,450-14,583 cP. The starches showed consistent thermal behavior since the TGA curves showed three stages with gelatinization temperatures that ranged between 54.9 and 59.75 °C, an enthalpy of 3.60-6.62 J/g, and various shapes of particles such as circular, elliptical, and oval. In conclusion, the relationships between variables such as water absorption index, swelling power, viscosity, crystallinity, enthalpy, and gelatinization temperature reveal different characteristics of each type of starch, which can influence its use.

Relationship between microstructure formation and in vitro starch digestibility in baked gluten-starch matrices.

Increased prevalence of diabetes prompts the development of foods with reduced starch digestibility. This study analyzed the impact of adding soluble dietary fiber (inulin-IN; polydextrose-PD) to baked gluten-starch matrices (7.5-13%) on microstructure formation and in vitro starch digestibility. IN and PD enhanced water-holding capacity, the hardness of baked matrices, and lowered water activity in the formulated matrices, potentially explaining the reduced starch gelatinization degree as IN or PD concentration increased. A maximum gelatinization decrease (26%) occurred in formulations with 13% IN. Micro-CT analysis showed a reduction in total and open porosity, which, along with the lower gelatinization degree, may account for the reduced in vitro starch digestibility. Samples with 13% IN exhibited a significantly lower rapidly available glucose fraction (8.56 g/100 g) and higher unavailable glucose fraction (87.76 g/100 g) compared to the control (34.85 g/100 g and 47.59 g/100 g, respectively). These findings suggest the potential for developing healthier, starch-rich baked foods with a reduced glycemic impact.

Morphological, textural analysis and freeze-thaw stability of starches from legume grow in Cameroon / Análise morfológica, textural e de estabilidade de congelamento-descongelamento de amidos de leguminosas cultivadas em Camarões

Starches from some legume grown in Cameroon were evaluated for their granule structure and size, turbidity, firmness and gel strength, thermal and freeze-thaw properties. Amylose contents were in the range of 26.21%-44.85%. Morphological analysis of the starch granules showed bimodal distribution, multiple sizes and shapes from small spherical to the bigger kidney shape. Significant differences were observed among starch in light transmittance, firmness and gel strength. The thermal parameters of starches were evaluated using differential scanning calorimeter and significant differences were observed. The peak gelatinisation temperature was positively correlated to starch granule size but the amylose content showed no evidence of their impact on legume starch properties studied. The data reported can be useful to facilitate the selection of variety of legume and conditions closer to the desired application.

Neste trabalho, amidos de algumas leguminosas cultivadas em Camarões foram avaliados quanto à estrutura e tamanho dos grânulos, turbidez, firmeza e resistência do gel, propriedades térmicas e de congelamento e descongelamento. Os conteúdos de amilose estavam na faixa de 26,21% a 44,85%. A análise morfológica dos grânulos de amido mostrou distribuição bimodal, múltiplos tamanhos e formas desde o pequeno esférico até o maior formato de rim. Diferenças significativas foram observadas entre os amidos na transmissão de luz, firmeza e força do gel. Os parâmetros térmicos dos amidos foram avaliados usando calorímetro diferencial de varredura e diferenças significativas foram examinadas. A temperatura de pico de gelatinização foi positivamente correlacionada com o tamanho do grânulo de amido, no entanto, o teor de amilose não mostrou evidência de impacto nas propriedades do amido de leguminosas estudadas. Os dados informados podem ser úteis para facilitar a seleção de variedades de leguminosas e condições mais próximas da aplicação desejada.

Effect of Ball-Milling on Starch Crystalline Structure, Gelatinization Temperature, and Rheological Properties: Towards Enhanced Utilization in Thermosensitive Systems.

Starch's crystalline structure and gelatinization temperature might facilitate or hinder its use. Ball milling has frequently been mentioned in the literature as a method for reducing starch size and as a more environmentally friendly way to change starch, such as by increasing surface area and reactivity, which has an impact on other starch properties. In this study, starch samples were milled for varying durations (1, 5, 10, 20, and 30 h) and at different starch-to-ball mass ratios (1:6 and 1:20). Microscopy and XRD revealed that prolonged milling resulted in effective fragmentation and a decrease in crystallinity of the starch granules. Increasing milling times resulted in an increase in amylose content. Rheology and thermal studies revealed that gelatinization temperatures dropped with milling duration and that viscosity and thixotropy were directly influenced. The samples milled for 10, 20, and 30 h at a ratio of 1:20 were the most fragmented and upon drying formed a transparent film at ambient temperature, because of the lower gelatinization temperature. Starch ball milling could lead to the use of this material in thermosensitive systems.

Characterization and Evaluation of Heat-Moisture-Modified Black and Red Rice Starch: Physicochemical, Microstructural, and Functional Properties.

This study sought to evaluate starch from black and red rice modified by heat-moisture, investigating the extraction yield, starch and amylose content, color, and phenolic compounds. The water and oil absorption capacity, whole milk and zero lactose absorption index, syneresis index, and texture were also analyzed. Microstructural analysis included Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The heat-moisture treatment (HMT) reduced the extraction yield and the starch and amylose content, with native black rice starch having the highest values for these parameters. The modification also affected the color and phenolic compounds of the starch, making it darker and changing its appearance. The modification improved the absorption of water, oil, and milk, reducing syneresis and increasing stability during storage. The starch surface was altered, especially for modified black rice starch, with larger agglomerates. The type of starch also changed from A to Vh, with lower relative crystallinity. The textural properties of modified red rice starch were also significantly altered. The HMT proved to be a viable and economical option to modify the analyzed parameters, influencing the texture and physicochemical properties of pigmented rice starch, expanding its applications, and improving its stability during storage at temperatures above 100 °C.

Modification of red rice starch by a combination of hydrothermal pretreatments and α-amylase hydrolysis.

The objective of this study was to evaluate the modification of red rice starch by a combination of hydrothermal pretreatments and α-amylase hydrolysis. In vitro digestibility and the morphological, structural, functional, thermal, textural and rheological properties of red rice starch were evaluated. The starch submitted to autoclave (A3) obtained the highest hydrolysis yield (37.66 %) after 300 min. The morphological analysis showed that for the native starch, the granules presented a polyhedral shape and increased in diameter (2.36-394.12 µm) due to hydrothermal pre-treatments. α-Amylase (9 U mg-1) from Aspergillus oryzae modified the structure of red rice starch, presenting technological properties different from native starch. X-ray diffraction (XDR) were altered after the starch granules were cooked, showing a rupture in the amylose and amylopectin molecules, which justifies the greater absorption capacity of oil and milk. Cohesiveness, adhesiveness and apparent viscosity decreased according to HPT temperature and pressure, as well as α-amylase action.

Rheological and Thermal Study about the Gelatinization of Different Starches (Potato, Wheat and Waxy) in Blend with Cellulose Nanocrystals.

The goal of this work was to analyze the effect of CNCs on the gelatinization of different starches (potato, wheat and waxy maize) through the characterization of the rheological and thermal properties of starch-CNC blends. CNCs were blended with different starches, adding CNCs at concentrations of 0, 2, 6 and 10% w/w. Starch-CNC blends were processed by rapid visco-analysis (RVA) and cooled to 70 °C. Pasting parameters such as pasting temperature, peak, hold and breakdown viscosity were assessed. After RVA testing, starch-CNC blends were immediately analyzed by rotational and dynamic rheology at 70 °C. Gelatinization temperature and enthalpy were assessed by differential scanning calorimetry. Our results suggest that CNCs modify the starch gelatinization but that this behavior depends on the starch origin. In potato starch, CNCs promoted a less organized structure after gelatinization which would allow a higher interaction amylose-CNC. However, this behavior was not observed in wheat and waxy maize starch. Insights focusing on the role of CNC on gelatinization yielded relevant information for better understanding the structural changes that take place on starch during storage, which are closely related with starch retrogradation. This insight can be used as an input for the tailored design of novel materials oriented towards different technological applications.

Germination of White and Red Quinoa Seeds: Improvement of Nutritional and Functional Quality of Flours.

Quinoa is an Andean grain, classified as pseudocereal and the exploitation of its nutritional profile is of great interest for the cereal-based industry. The germination of quinoa seeds (white and red royal) was tested at 20 °C for different times (0, 18, 24 and 48 h) to select the best conditions for improving the nutritional quality of their flours. Changes in proximal composition, total phenolic compounds, antioxidant activity, mineral content, unsaturated fatty acids and essential amino acids profiles of germinated quinoa seeds were determined. In addition, changes in structure and thermal properties of the starch and proteins as consequence of germination process were analyzed. In white quinoa, germination produced an increase in the content of lipids and total dietary fiber, at 48 h, the levels of linoleic and α-linolenic acids and antioxidant activity increase, while in red quinoa, the component that was mostly increased was total dietary fiber and, at 24 h, increased the levels of oleic and α-linolenic acids, essential amino acids (Lys, His and Met) and phenolic compounds; in addition, a decrease in the amount of sodium was detected. On the basis of the best nutritional composition, 48 h and 24 h of germination were selected for white and red quinoa seeds, respectively. Two protein bands were mostly observed at 66 kDa and 58 kDa, being in higher proportion in the sprouts. Changes in macrocomponents conformation and thermal properties were observed after germination. Germination was more positive in nutritional improvement of white quinoa, while the macromolecules (proteins and starch) of red quinoa presented greater structural changes. Therefore, germination of both quinoa seeds (48 h-white quinoa and 24 h-red quinoa) improves the nutritional value of flours producing the structural changes of proteins and starch necessary for obtaining high quality breads.

Starch synthesis and gelatinization properties of potato tubers / Síntese de amido e propriedades de gelatinização de tubérculos de batata com diferentes teores de amido

Biosynthesis is the only source of potato starch which is an important raw material for food processing, modified starch and biomass energy. However, it is not clear about the evolution of starch synthesis with tuber development in potato. The present study evaluated the differences of starch synthesis and gelatinization properties of potato tubers with different starch content. Relative to cultivars of medium and low starch content, cultivars of high starch content showed significantly higher SBEII gene expression, AGPase and SSS enzyme activity, and total starch content after middle stage of starch accumulation, and had smaller average starch granule size during whole process of tuber development, and had higher pasting temperature before late stages of tuber growth, and had lower pasting temperature after middle stage of starch accumulation. Path analysis showed that, after middle stage of starch accumulation, effects on starch gelatinization of cultivars with high, medium and low starch content represented starch synthesis enzyme activity > starch accumulation > starch granule distribution > starch synthesis enzyme gene expression, starch synthesis enzyme gene expression > starch synthesis enzyme activity > starch accumulation > starch granule distribution, starch synthesis enzyme gene expression > starch granule distribution > starch synthesis enzyme activity > starch accumulation, respectively. In the study, phases existed in the starch biosynthesis of potato tuber, and the starch quality and its formation process were different among varieties with different starch content. The findings might contribute to starch application and potato industries.

A biossíntese é a única fonte de amido de batata que é uma importante matéria-prima para o processamento de alimentos, amido modificado e energia de biomassa. No entanto, não está claro sobre a evolução da síntese do amido com o desenvolvimento do tubérculo na batata. O presente estudo teve como objetivo avaliar as diferenças nas propriedades de síntese e gelatinização do amido de tubérculos de batata com diferentes teores de amido. Em relação às cultivares de médio e baixo teor de amido, as cultivares de alto teor de amido apresentaram expressão do gene SBEII, atividade enzimática AGPase e SSS e teor de amido total significativamente maiores após o estágio intermediário de acúmulo de amido, bem como menor tamanho médio dos grânulos de amido durante todo o processo de desenvolvimento do tubérculo, maior temperatura de colagem antes dos estágios finais de crescimento do tubérculo e menor temperatura de colagem após o estágio intermediário de acúmulo de amido. A análise de trilha mostrou que, após o estágio intermediário de acúmulo de amido, os efeitos na gelatinização do amido de cultivares com alto, médio e baixo teor de amido representaram a atividade da enzima de síntese de amido> acúmulo de amido> distribuição de grânulos de amido> expressão gênica de enzima de síntese de amido; expressão gênica de enzima de síntese de amido > atividade da enzima de síntese de amido> acúmulo de amido> distribuição de grânulos de amido; expressão gênica da enzima de síntese de amido> distribuição de grânulos de amido> atividade de síntese de amido> acúmulo de amido, respectivamente. No estudo, as fases existentes na biossíntese do amido do tubérculo de batata, e a qualidade do amido e seu processo de formação foram diferentes entre as variedades com diferentes teores de amido. As descobertas podem contribuir para a aplicação de amido e as indústrias de batata.

Effects of thermal energy on extrusion characteristics, digestibility and palatability of a dry pet food for cats.

The influence of specific thermal energy (STE) applications on extruder preconditioner was evaluated in a dry food for cats. In the first study, six STE applications were tested with mass temperatures of 45°C, 55°C, 65°C, 75°C, 85°C and 95°C. The extrusion parameters, starch gelatinization and kibble formation were evaluated. Diets were given to cats to evaluate digestibility, faecal characteristics and palatability. In the second experiment, three treatments were compared: low STE-a preconditioner temperature of 45°C (L STE); high STE-a preconditioner temperature of 95°C (H STE); high STE (preconditioner temperature of 95°C) combined with an increase in the mass flow rate to obtain a motor amperage similar to that of the L STE (H STEflow ). Data were analysed by polynomial contrasts (Experiment 1) or Tukey's test (Experiment 2; p < 0.05). An increase in STE reduced motor amperage, mass pressure and specific mechanical energy (SME) implementation (p < 0.001) and increased total specific energy (TSE) and mass temperature (p < 0.01). The increase in STE induced greater kibble expansion and starch gelatinization (p < 0.001). No changes in apparent nutrient digestibility or faeces characteristics were observed (p > 0.05). Lower STE and starch gelatinization induced higher butyrate and total volatile fatty acid (VFA) contents in faeces (p < 0.01). Cats showed greatest preference for the formulation with the highest STE (p < 0.01). In the second experiment, when the motor amperage was increased in the H STEflow treatment to a value similar to that of the L STE, the mass flow rate increased 40%, and the electric energy consumption remained unchanged (p < 0.001), with gains observed for efficiency and cost. In conclusion, STE application is important for sufficient TSE implementation, enhancing kibble expansion, starch gelatinization, cat preferences for food, extruder productivity and reducing SME application. Foods with lower starch gelatinization lead to increased VFA in faeces, with possible implications for gut health.

The Effect of Arabinoxylan and Wheat Bran Incorporation on Dough Rheology and Thermal Processing of Rotary-Moulded Biscuits.

Wheat bran incorporation into biscuits may increase their nutritional value, however, it may affect dough rheology and baking performance, due to the effect of bran particles on dough structure and an increase in water absorption. This study analyzed the enrichment effect of wheat bran and arabinoxylans, the most important non-starch polysaccharides found in whole wheat flour, on dough rheology and thermal behaviour during processing of rotary-moulded biscuits. The objective was to understand the contribution of arabinoxylans during biscuit-making and their impact when incorporated as wheat bran. Refined flour was replaced at 25, 50, 75, or 100% by whole flour with different bran particle sizes (fine: 4% > 500 µm; coarse: 72% > 500 µm). The isolated effect of arabinoxylans was examined by preparing model flours, where refined flour was enriched with water-extractable and water-unextractable arabinoxylans. Wheat bran had the greatest impact on dough firmness and arabinoxylans had the greatest impact on the elastic response. The degree of starch gelatinization increased from 24 to 36% in biscuits enriched with arabinoxylans or whole flour and coarse bran. The microstructural analysis (SEM, micro-CT) suggested that fibre micropores may retain water inside their capillaries which can be released in a controlled manner during baking.

Influence of gelatinization degree and octenyl succinic anhydride esterification on the water sorption characteristics of corn starch.

The effects of gelatinization degree (GD) and octenyl succinic anhydride (OSA) esterification in the sorption-desorption characteristics of normal corn starch (NCS) were studied. NCS was subjected to different GD (53, 70, and 96%) with an extruder and lyophilized. FTIR analysis revealed that GD increased the hydrated (995/1022 ratio) and decreased the short-range ordered (1022/1047 ratio). The equilibrium sorption-desorption curve of starches was obtained for water activities up to 0.95 and fitted with the Guggenheim-Anderson-de Boer (GAB) model. Gelatinization of corn starch decreased its water sorption capacity, increased its sorption hysteresis and decreased its monolayer moisture content. OSA treatment of NCS reduced the water sorption capacity, hysteresis, and monolayer moisture content as reflected by slight variations of these parameters with the GD. A principal component analysis showed that GD and OSA esterification are mutually independent treatments, which can provide different effects on the water sorption characteristics of NCS.

Characterization of starches obtained from several native potato varieties grown in Cusco (Peru).

Ten native potato varieties grown in Cusco (at 3,672 m above sea level) were used for starches extraction (at a pilot scale), and their physicochemical, functional, morphological, and structural characteristics were assessed. The content of protein, apparent amylose and phosphorus ranged from 0.1% to 0.44%, 23.42% to 35.5%, and 0.07 to 0.10%, respectively. Starch granules revealed smooth surface, with ellipsoidal and spherical shapes, particle size analysis exhibited bimodal or multimodal distribution, while the averaged crystallinity was 27.7% assessed by XRD. Gelatinization temperatures of the starches ranged from 57.4 to 60.1 °C, 60.8 to 64.3 °C, and 68.4 to 71.1°C for To, Tp, and Tc, respectively; and the gelatinization enthalpies ranged from 15.4 to 17.1 J/g. Respect to pasting properties, the peak viscosity and setback viscosity ranged from 12,970 to 16,970 mPa⋅s and from 968 to 2498 mPa⋅s, respectively. Thermogravimetric analysis (TGA) revealed no significant relationship between apparent amylose content and thermal stability. Therefore, the results reveal subtle differences in the functional characteristics of the starches from the native varieties of potato studied, which can be recommended for food industry applications. PRACTICAL APPLICATION: This study contributes to show several varieties of native potatoes from Cusco and their valorization as nonconventional starch source. Describing the physicochemical, functional, and structural characteristics of these starches could be useful for food industry applications.

Evaluation of wheat flour substitution type (corn, green banana and rice flour) and concentration on local dough properties during bread baking.

Different bread formulations, which provide different dough structures, were studied in order to better understand the effect of wheat flour substitution, flour type and concentration on dough development during baking, and their relationship with physical properties of the final product. Breads were produced with partial substitution of wheat flour by corn (CF), green banana (GF) and rice flour (RF), at different concentrations, and then baked at different times. Wheat flour substitution by CF, GF and RF in bread reduces heat transfer to the dough center by about 21%, 35% and 20%, respectively; and the water loss by about 5%, 15% and 0%, respectively. Those reductions were more influenced by flour type, than flour concentration. When wheat flour is substituted, the mechanisms of water migration are modified, once the pore system of bread dough is more discrete and stiffens later. Calculated thermal conductivity and diffusivity of the different flours used, and its correlations with average composite-bread heating rates (0.93) and water loss (0.85), respectively, indicates that thermal properties of composite bread dough could represent an important issue to be explored in dough systems with reduced gluten concentration.

Nutritional and technological properties of a quinoa (Chenopodium quinoa Willd.) spray-dried powdered extract.

The relevance of an appropriate nutrition requires innovation in the design of food ingredients. The goal of this work was to obtain a powdered extract of quinoa by using spray-drying. To this aim, quinoa flour was suspended in water to obtain a soluble fraction mainly composed of proteins, starch, fiber, lipids, antioxidants and minerals. The spray-drying conditions of this quinoa soluble fraction were set-up in terms of inlet temperatures (150, 160, 170 and 180 °C) and feed flow (4.5, 7.5, 10.5 mL/min). The obtained powders were characterized by determining the proximate composition, antioxidant activity, microstructure, fatty acids' profile, and starch and proteins' structures. A correlation among the drying parameters and the chemical and functional attributes of the powders was addressed using principal component analysis. From a technological viewpoint the use of moderate feed flows (7.5 mL/min) and high inlet temperatures (180 °C) was the best combination to obtain high powder yields (85% d.b.), low aw (0.047 ± 0.005) and high solids content (0.956 ± 0.005). The drying temperature positively affected the structure of starch, improving swelling and favoring moderate agglomeration which increases the encapsulation properties of quinoa. These results support the use of spray-drying as a suitable method to obtain powdered extracts of quinoa without affecting the nutritional value, thus supporting their use as functional ingredients in the formulation of ready-to-eat foods.

Flour functional properties of purple maize (Zea mays L.) from Argentina. Influence of environmental growing conditions.

The objective was to characterize thermal and viscosity properties of flour of purple maize from Argentina, and to evaluate the environmental effects on composition and flour properties. Half-sib families were selected from original germplasm and reproduced during 2014 and 2015. Chemical composition, thermal and pasting properties of whole grain flour were determined. Non-purple genotypes were used as controls. Composition of purple maize did not show significant differences with controls, but amylose content was significantly lower. High variability in pasting and thermal properties of flour was observed between genotypes. Anthocyanin content positively correlated with breakdown (r = 0.37, P < 0.05), indicating that anthocyanins increased starch granules fragility during cooking. The higher gelatinization enthalpy of purple genotypes was coincident with the lower amylose content in relation to non-purple. The amylopectin retrogradation enthalpy negatively correlated with polyphenols (r = -0.35, P < 0.05) and anthocyanins (r = -0.40, P < 0.05), probably due to interactions formed after starch gelatinization. Flour functionality parameters showed higher effect of genotype and lower effects of environment and genotype × environment interaction. The variability found among genotypes indicates different flour behavior that would facilitate the identification of progenies with particular properties for production of functional maize based-foods.

Physicochemical, functional and morphological characterization of starches isolated from three native potatoes of the Andean region.

Three varieties of native potato (Imilla blanca, Imilla negra and Loc'ka) that grow in the Andean region at more than 3800 m.a.s.l. were selected fot the extraction and characterization or their starch. Instrumental techniques such as scanning electron microsocopic (SEM), differential scanning calorimetry (DSC), Fourier transformed infrarred spectroscopy (FTIR), X-ray diffraction, colorimetry and polarized light microscopy were used. The results showed that only Loc'kás starch had a unimodal granule size distribution, whereas Imilla negra and Imilla blanca starches showed two and three granule size populations, respectively. The starch from Imilla negra showed higher apparent amylose content, peak viscosity, phosphorous content and paste clarity. The starch from Imilla blanca showed high relative crystallinity, while Imilla blanca and Imilla negra had higher intensity ratios than that from Loc'ka, suggesting high molecular order. Cooked starch from Imilla negra showed higher resistant starch (RS) fraction than the other starches studied.

Physicochemical, Thermal, Structural and Pasting Properties of Unconventional Starches from Ginger (Zingiber officinale) and White Yam (Dioscorea sp)

Abstract Ginger and white yam starches were investigated and compared with maize starch. Proximal composition, thermogravimetry, differential scanning calorimetry, microscopy, colourimetry, X-ray powder diffractometry and pasting profile were analysed. The unconventional starches presented higher protein and ash contents than the maize starch, that had the highest thermal stability. Higher gelatinisation temperatures were reported for ginger starch, and the enthalpy of the unconventional starches were similar. The maize starch presented the lowest gelatinisation values. For the corn starch the granules were polygonal and smaller than the unconventional starches, and oval shapes and larger diameters were found for the ginger and yam starches. The unconventional starches presented less brightness and a greater tendency to red and yellow. The maize and ginger starches had A-type diffraction patterns, while the white yam starch had a C-type pattern. The highest relative crystallinity was observed for the ginger starch and there were small differences between the yam and maize starches. Higher peak viscosity and final viscosity and lower pasting temperature were observed for the yam starch. Ginger starch showed the highest shear and stability of heating glue, so may be used in products processed under high temperatures; and yam starch can be used in acidic foods that require high viscosities.

The effects of gelatin supplementation prior to cooling on ram semen quality and fertility

The physical and chemical characteristics of gelatin have been used to justify its inclusion in extenders to preserve the sperm quality and improve results of cervical artificial insemination with cooled semen. The objective of this study was to evaluate the effects of gelatin supplementation in cooling extender on the quality and fertility of ram semen stored at 5°C. Semen samples (n = 24) of Santa Inês rams (n = 6) were diluted in Glycine-Yolk-Milk extender without (control) or with 1.5% of gelatin. The samples were loaded into 0.25 mL straws, cooled to 5°C and stored vertically for 48 and 72 hours. Sample quality was evaluated using straw homogeneity tests based on pH, osmolality and the proportion of spermatozoa (PS) in both upper and lower segments of straws (US and LS), analyses of sperm motility, plasma and acrosomal membrane integrity, and by fertility after artificial insemination. Differences between the US and LS of straws were found for pH and PS (%). They were significant only in the control group at both times: pH – 5.96 vs. 5.71 at 48 h and 6.13 vs. 5.89 at 72 h; PS – 21.66 vs. 78.34 at 48 h and 20.87 vs. 79.13 at 72 h. Storage in gelatin had very little, to no effect on the sperm kinetics or on the sperm membrane integrity evaluations. The addition of gelatin to the extender did not affect the pregnancy rate which ranged from 4.4 to 26.1%. We conclude that gelatin is effective in maintaining the physical and chemical homogeneity of the semen samples. Further research is needed in order to optimize the use of gelatin supplementation and elucidate any potential benefits.

The effects of gelatin supplementation prior to cooling on ram semen quality and fertility

The physical and chemical characteristics of gelatin have been used to justify its inclusion in extenders to preserve the sperm quality and improve results of cervical artificial insemination with cooled semen. The objective of this study was to evaluate the effects of gelatin supplementation in cooling extender on the quality and fertility of ram semen stored at 5°C. Semen samples (n = 24) of Santa Inês rams (n = 6) were diluted in Glycine-Yolk-Milk extender without (control) or with 1.5% of gelatin. The samples were loaded into 0.25 mL straws, cooled to 5°C and stored vertically for 48 and 72 hours. Sample quality was evaluated using straw homogeneity tests based on pH, osmolality and the proportion of spermatozoa (PS) in both upper and lower segments of straws (US and LS), analyses of sperm motility, plasma and acrosomal membrane integrity, and by fertility after artificial insemination. Differences between the US and LS of straws were found for pH and PS (%). They were significant only in the control group at both times: pH 5.96 vs. 5.71 at 48 h and 6.13 vs. 5.89 at 72 h; PS 21.66 vs. 78.34 at 48 h and 20.87 vs. 79.13 at 72 h. Storage in gelatin had very little, to no effect on the sperm kinetics or on the sperm membrane integrity evaluations. The addition of gelatin to the extender did not affect the pregnancy rate which ranged from 4.4 to 26.1%. We conclude that gelatin is effective in maintaining the physical and chemical homogeneity of the semen samples. Further research is needed in order to optimize the use of gelatin supplementation and elucidate any potential benefits.(AU)