Valorization of the Salmon Frame as a High-Calcium Ingredient in the Formulation of Nuggets: Evaluation of the Nutritional and Sensory Properties.

In the Chilean population, calcium consumption is deficient. Therefore, several strategies have been implemented to increase calcium intake, such as consuming dairy products and supplements. In this study, an ingredient composed of bone flour (BF) and protein hydrolysate (PH) obtained from salmon frame was used as an innovative source of calcium. The objective was to evaluate the effect of the incorporation of BF and PH in a 1:1 ratio (providing two calcium concentrations to the nuggets, 75 and 125 mg/100 g) on calcium content and sensory attributes of salmon nuggets submitted to baking or shallow frying. Proximal chemical analyses, fatty acid composition, calcium content, and sensory evaluation (acceptability and check-all-that-apply test) were tested in the nuggets. The incorporation of BF/PH (1:1) in both concentrations increased the calcium content of salmon nuggets being higher for the 125 mg/100 g. On the other hand, no negative effects were observed on sensory properties where all samples showed good overall acceptability for baked and fried nuggets. Therefore, the incorporation of BF/PH (1:1) into salmon nuggets enhances the nutritional quality of these products by providing a higher calcium content without significantly affecting their sensory properties.

Fish Bones as Calcium Source: Bioavailability of Micro and Nano Particles.

The amount of by-products/waste in the fish industry is roughly 50%. Fish bones could be used to produce nanoparticles, which may have potential use in the food industry as a novel calcium source and at the same time, contribute to reduce waste production. The objective of this study was to evaluate the bioavailability of nano-size salmon fish bone particles compared to micro-size salmon fish bone particles, and calcium carbonate. The study was carried out in 21-28-day-old C57BL/6 male mice fed for 21 days with the experimental diets. The groups were as follows: CaCO3 0.5% Ca (CN 0.5); CaCO3 1.0% Ca (CN 1.0); salmon fish bone (SFB) microparticles 0.5% Ca (MP 0.5); SFB microparticles 1.0% Ca (MP 1.0); SFB nanoparticles 0.5% Ca (NP 0.5); and SFB nanoparticles 1.0% Ca (NP 1.0). Calcium bioavailability, defined as the percent calcium in femur showed an increasing trend from CN 0.5 to NP 1.0 group. According to ANCOVA, the greatest Ca content was observed in the NP 1.0 group compared with all groups but NP 0.5. In conclusion, in a murine model, salmon fish bone nanoparticles present higher calcium bioavailability than salmon fish bone microparticles, and both, in turn, have better bioavailability than calcium carbonate.

Enzymatic Hydrolysis of Salmon Frame Proteins Using a Sequential Batch Operational Strategy: An Improvement in Water-Holding Capacity.

The meat industry uses phosphates to improve the water-holding capacity (WHC) of meat products, although excess phosphates can be harmful to human health. In this sense, protein hydrolysates offer an alternative with scientific evidence of improved WHCs. Salmon frames, a byproduct rich in protein, must be processed for recovery. Enzymatic technology allows these proteins to be extracted from muscle, and the sequential batch strategy significantly increases protein nitrogen extraction. This study focused on evaluating the WHC of protein hydrolysates from salmon frames obtained through double- and triple-sequential batches compared to conventional hydrolysis. Hydrolysis was carried out for 3 h at 55 °C with 13 mAU of subtilisin per gram of salmon frames. The WHC of each hydrolysate was measured as the cooking loss using concentrations that varied from 0 to 5% (w/w) in the meat matrix. Compared with those obtained through conventional hydrolysis, the hydrolysates obtained through the strategy of double- and triple-sequence batches demonstrated a 55% and 51% reduction in cooking loss, respectively, when they were applied from 1% by weight in the meat matrix. It is essential to highlight that all hydrolysates had a significantly lower cooking loss (p ≤ 0.05) than that of the positive control (sodium tripolyphosphate [STPP]) at its maximum allowable limit when applied at a concentration of 5% in the meat matrix. These results suggest that the sequential batch strategy represents a promising alternative for further improving the WHC of hydrolysates compared to conventional hydrolysis. It may serve as a viable substitute for polyphosphates.

Application of CO2-Laser Micro-Perforation Technology to Freeze-Drying Whole Strawberry (Fragaria ananassa Duch.): Effect on Primary Drying Time and Fruit Quality.

Freeze-drying (FD) processing preserves foods by combining the most effective traditional technologies. FD conserves the structure, shape, freshness, nutritional/bioactive value, color, and aroma at levels similar to or better than those of refrigerated and frozen foods while delivering the shelf-stable convenience of canned/hot-air-dehydrated foods. The mass transfer rate is the essential factor that can slow down the FD process, resulting in an excessive primary drying time and high energy consumption. The objective of this study was to reduce the FD processing time using CO2 laser technology to improve product competitiveness in the preservation of whole strawberries. The research process consisted of the selection and characterization of fresh strawberries, followed by preparation, pre-treatment, freeze-drying, a primary drying time assessment, and a quality comparison. Experiments were carried out using strawberries without micro-perforation and with five and eight micro-perforations. Quality parameters were determined for fresh, frozen/thawed, and freeze-dried/rehydrated strawberries. It was found that the primary drying time can be significantly reduced by 20% (95% CI) from 26.7 h for non-perforated fruits to 22.3 h when five micro-perforations are made on each strawberry. The quality parameters used to evaluate the strawberries did not show significant differences when comparing frozen/thawed fruits with freeze-dried/rehydrated fruits. The experiments conducted in this study showed that freeze-drying may efficiently compete with freezing technology when processing whole strawberries.

Effect of Adding Bovine Skin Gelatin Hydrolysates on Antioxidant Properties, Texture, and Color in Chicken Meat Processing.

(1) Background: Phosphates are used in the food industry to improve water retention and product quality. However, when consumed in excess, they can be harmful to health. Instead, bovine skin gelatin hydrolysates present health benefits such as being a rejuvenating agent, stimulating collagen production, and improving food quality, in addition to being a source of protein. The effect of the addition of bovine skin gelatin hydrolysates on the texture and color of thermally processed chicken meat (boiled type) and antioxidant activity was evaluated. (2) Methods: Hydrolysates were prepared with subtilisin with the degree of hydrolysis being 6.57 and 13.14%, which were obtained from our previous study. (3) Results: The hydrolysates improved the firmness of the meat matrix compared to the control. Additionally, the hydrolysate with a 13.14% degree of hydrolysis reached the same firmness (p > 0.05) as the commercial ingredient sodium tripolyphosphate at its maximum limit allowed in the food industry when it was applied at 5% (w/w meat) in the meat matrix, improving firmness over the control by 63%. Furthermore, both hydrolysates reached a similar color difference to sodium tripolyphosphate at its maximum allowed limit when applied at a concentration of 2% (w/w meat). Additionally, it was found that these hydrolysates obtained the same antioxidant activity as sodium tripolyphosphate, capturing free radicals at 10%. (4) Conclusion: The findings of this study suggest that bovine skin gelatin hydrolysates can be applied as an ingredient with functional properties, being an alternative to phosphates to improve the quality of meat products.

Assessing the Enzymatic Hydrolysis of Salmon Frame Proteins through Different By-Product/Water Ratios and pH Regimes.

The enzymatic hydrolysis of fish by-product proteins is traditionally carried out by mixing ground by-products with water. In addition, pH control is used to avoid pH drops. Higher costs are involved due to the use of pH control systems and the consequent energy cost in the drying stage. This work aimed to evaluate the effect of these conditions on the hydrolysis of salmon frame (SF) proteins, including the SF hydrolysis without added water. SF hydrolysis by subtilisin at 50, 75, and 100% SF under different pH regimes were evaluated by released α-amino (α-NH) groups, total nitrogen, degree of hydrolysis, and estimated peptide chain length (PCL) at 55 °C. The concentration of released α-NH groups was higher in the conditions with less added water. However, the nitrogen recovery decreased from 50 to 24% at 50 and 100% SF, respectively. Changing the SF/water ratio had a more significant effect than changing the pH regime. Estimated PCL changed from 5-7 to 7-9 at 50 and 100% SF, respectively. The operating conditions affected the hydrolysis performance and the molecular characteristics of the hydrolysate.

Variable Retort Temperature Profiles (VRTPs) and Retortable Pouches as Tools to Minimize Furan Formation in Thermally Processed Food.

Furan and its derivates are present in a wide range of thermally processed foods and are of significant concern in jarred baby and toddler foods. Furan formation is attributed to chemical reactions between a variety of precursors and a high processing temperature. Also, some kinetic models to represent its formation in different food materials have been studied and could predict the furan formation under simulated operating conditions. Therefore, this review aims to analyze and visualize how thermally processed foods might be improved based on optimal control of processing temperature and package design (e.g., retort pouches) to diminish furan formation and maximize quality retention. Many strategies have been studied and applied to reduce furan levels. However, an interesting approach that has not been explored is the thermal process design based on optimum variable retort temperature profiles (VRTPs) and the use of retortable pouches considering the microstructural changes of food along the process. The target of process optimization would be developed by minimizing the microstructural damage of the food product. It could be possible to reduce the furan level and simultaneously preserve the nutritional value through process optimization.

Comparison of Microwave Short Time and Oven Heating Pretreatment on Crystallization of Raisins.

Crystalline material can develop on the surface of raisins during storage and transport, affecting the final acceptability of the product. In this work, a mild thermal pretreatment was applied to raisins to melt the pre-existing crystals and the effect of such thermal treatments on the development of crystals over a storage period was investigated. The raisins selected for this study were of the Thompson seedless variety from one Chilean company. The thermal pretreatment of raisins at 50 °C and 70 °C for 20 min in an oven and microwave (800 W) irradiation for 15 s resulted in a reduction in the percentage of crystallized raisins (w/w) from more than 50% in the control samples to less than 10% after 35 days of storage at 15 and 25 °C in a 57% relative humidity environment. The results showed that some textural parameters, such as cohesiveness and chewiness, were not affected by thermal treatment and were independent of storage temperature.

Collagen as a source of bioactive peptides: a bioinformatics approach

BACKGROUND: Collagen is the most abundant protein in animals and can be obtained from residues of the food industry. Its hydrolysate has many desirable properties that make it suitable as an additive in foods and cosmetics, or as a component of scaffold materials to be used in biomedicine. RESULTS: We report here the characterization of type I collagen from five different sources, namely bovine, porcine, chicken, trout and salmon, as well as their hydrolysates by means of bioinformatics tools. As expected, the results showed that bovine and porcine collagen, as well as trout and salmon collagen, can be used interchangeably due to their high identity. This result is consistent with the evolution of proteins with highly identical sequences between related species. Also, 156 sequences were found as potential bioactive peptides, 126 from propeptide region and 30 from the central domain, according to the comparison with reported active sequences. CONCLUSIONS: Collagen analysis from a bioinformatic approach allowed us to classify collagen from 5 different animal sources, to establish its interchangeability as potential additive in diverse fields and also to determine the content of bioactive peptides from its in silico hydrolysis.

Bovine skin gelatin hydrolysates as potential substitutes for polyphosphates: The role of degree of hydrolysis and pH on water-holding capacity.

The effects of adding bovine skin gelatin hydrolysate obtained with subtilisin, on water-holding capacity (WHC), in a thermally processed chicken meat model, were investigated. Hydrolysates with different degrees of hydrolysis (DH) (6.57%, 13.14%, and 26.28%) were prepared. The results showed that all the tested hydrolysates improved water retention in the meat matrix. The hydrolysate with 26.28% DH showed similar behavior throughout the full range of concentrations [0% to 5% w/w] compared to that of the positive control (sodium tripolyphosphate [STPP]). In addition, the other hydrolysates [6.57% DH and 13.14% DH at 3% and 2.5% w/w concentrations, respectively] showed behaviors that coincided with that of STPP at its maximum limit allowed. A correlation was observed between the WHC and the pH of the meat samples treated with each hydrolysate or STPP. In addition, it was found that the WHC of the hydrolysates was due to increases in pH and the specific effects of the hydrolysate beyond the typical effects of pH and ionic strength in meat systems. The solubility of all hydrolysates was high (>90%). In conclusion, bovine skin gelatin hydrolysates could serve as an alternative to polyphosphates to improve water retention and the functional properties of thermally processed meat products. PRACTICAL APPLICATION: This study investigated the effects of adding bovine skin gelatin hydrolysate obtained with subtilisin on water-holding capacity (WHC) in a thermally processed chicken meat model. It was found that the hydrolysis of bovine skin gelatin with subtilisin can replace chemical products harmful to health, such as STPP, in terms of water-holding capacity. Therefore, bovine skin gelatin hydrolysate can be used as an ingredient in the formulation of thermally processed meat products.

Impact of thermal pretreatment on crystallization of Thompson raisins.

After prolonged storage or during the shipment of raisins, a crystalline material may be developed on their surface, affecting the final acceptability of the product. The mild thermal pretreatment (50 °C for a period of 12 h and 48 h) was applied to dissolve any potential tiny crystals and nuclei already present in the raisins. The thermal pretreatment of raisins resulted in a reduction on the percentage of crystallized raisins (w/w) from more than 46% in control samples to less than 10% after 30 days of storage at 57% and 66% of relative humidity and 15 °C and 25 °C. X-ray diffraction analysis identified d-Glucose monohydrate as the main crystalline component. All the thermal treatments increased the hardness of the raisins, when they were incubated at 57% relative humidity. To mitigate the problems of crystallization of raisins during shipping, it is recommended that the raisins are thermally pretreated and the shipping conditions are controlled.

Freeze-Drying of Blueberries: Effects of Carbon Dioxide (CO2) Laser Perforation as Skin Pretreatment to Improve Mass Transfer, Primary Drying Time, and Quality.

Freeze-dried berry fruits are generally consumed as they are, whole and without peeling or cutting, as the conservation of their original shape and appearance is often desired for the final product. However, usually, berries are naturally wrapped by an outer skin that imparts a barrier to vapor flow during freeze-drying, causing berry busting. Photo-sequence, experimental, and theoretical methodologies were applied to evaluate the application of CO2 laser microperforations to blueberry skin. Under the same set of freeze-drying conditions, blueberries with and without perforations were processed. The results showed that the primary drying time was significantly reduced from 17 ± 0.9 h for nontreated berries to 13 ± 2.0 h when nine microperforations per berry fruit were made. Concomitantly, the quality was also significantly improved, as the percentage of nonbusted blueberries at the end of the process increased from an average of 47% to 86%. From a phenomenological perspective, the analysis of the mass transfer resistance of nontreated fruits, in agreement with reported studies, showed a Type II curvature, with a sharp decrease at low time, followed by a linear increase. In contrast, blueberries with nine perforations depicted a Type III regime, with a saturation curvature toward the time axis. It was demonstrated that CO2-laser microperforation has high potential as a skin pretreatment for the freeze-drying of blueberries.

Crystallisation and glass transition behaviour of Chilean raisins in relation to their sugar compositions.

The effects of sugar component ratio, water fraction, and storage conditions on crystallisation and glass transition temperature (Tg) of three Chilean dried raisins were examined by using differential scanning calorimetry (DSC), polarised light microscopy and X-ray diffraction (XRD) techniques. Thompson, Flame and Golden raisins differed in fructose:glucose and glucose:water ratios, impacting on their measured Tgs (P < 0.05) and propensity of sugaring. The ratios of fructose:glucose (1:3, 1:2 and 1:1) and glucose:water (1.7, 1.9 and 2.1) also influenced the measured Tgs (P < 0.05) and sugaring of fructose-glucose-water model solutions. Measurement of Tgs in the raisins as a function of water activity (aw 0.11-0.74) showed that water acts as a strong plasticiser decreasing the Tgs (-16.4 to -61.6 °C). XRD results revealed that sugaring in Thompson raisins was delayed at low temperatures (5 & 15 °C) compared to that stored at 25 °C. The refrigeration may be a simple approach to delay the sugaring in raisins.

Measuring and predicting head space pressure during retorting of thermally processed foods.

UNLABELLED: Traditional metal cans and glass jars have been the mainstay in thermally processed canned foods for more than a century, but are now sharing shelf space with increasingly popular flexible pouches and semi-rigid trays. These flexible packages lack the strength of metal cans and glass jars, and need greater control of external retort pressure during processing. Increasing internal package pressure without counter pressure causes volumetric expansion, putting excessive strain on package seals that may lead to serious container deformation and compromised seal integrity. The primary objective of this study was to measure internal pressure build-up within a rigid air-tight container (module) filled with various model food systems undergoing a retort process in which internal product temperature and pressure, along with external retort temperature and pressure, were measured and recorded at the same time. The pressure build-up in the module was compared with the external retort pressure to determine the pressure differential that would cause package distortion in the case of a flexible package system. The secondary objective was to develop mathematical models to predict these pressure profiles in response to known internal temperature and initial and boundary conditions for the case of the very simplest of model food systems (pure water and aqueous saline and sucrose solutions), followed by food systems of increasing compositional complexity (green beans in water and sweet peas in water). Results showed that error between measured and predicted pressures ranged from 2% to 4% for water, saline, and green beans, and 7% to 13% for sucrose solution and sweet peas. PRACTICAL APPLICATION: Flexible packages have limited strength, and need more accurate and closer control of retort pressure during processing. The package becomes more flexible as it heats and might expand with increasing internal pressure that may cause serious deformation or rupture if not properly controlled and/or counterbalanced with external retort pressure. This article describes methods for determining exactly what the retort pressure profile will need to be to avoid this problem during retorting, and mathematical models to predict these pressures in response to known internal temperature and initial/boundary conditions.

Development of an ingredient containing apple peel, as a source of polyphenols and dietary fiber.

Apple peel is a waste product from dried apple manufacture. The content of phenolic compounds, dietary fiber, and mineral are higher in apple peel, compared to other edible parts of this fruits. The objective of this study was to develop an ingredient from Granny Smith apple peel, using a pilot scale double drum-dryer, as drying technology. The control of all steps to maximize the retention of phenolic compounds and dietary fiber was considered. Operational conditions, such as drying temperature and time were determined, as well as important preprocessing steps like grinding and PPO inhibition. In addition, the physical-chemical characteristics, mineral and sugar content, and technological functional properties such as water retention capacity, solubility index, and dispersability among others, were analyzed. A simple, economical, and suitable pilot scale process, to produce a powder ingredient from apple peel by-product, was obtained. The drying process includes the application of ascorbic acid at 0.5% in the fresh apple peel slurry, drum-dryer operational conditions were 110 degrees C, 0.15 rpm and 0.2 mm drum clearance. The ingredient developed could be considered as a source of phenolic compounds (38.6 mg gallic acid equivalent/g dry base) and dietary fiber (39.7% dry base) in the formulation of foods. Practical Application: A method to develop an ingredient from Granny Smith apple peel using a pilot scale double drum-dryer as drying technology was developed. The method is simple, economical, feasible, and suitable and maximizes the retention of phenolic compounds and dietary fiber present in the raw matter. The ingredient could be used in the formulation of foods.