Dr. Sergio Almonacid

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Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 August 2010 in Journal of Food Science

Journal Article

Development of an Ingredient Containing Apple Peel, as a Source of Polyphenols and Dietary Fiber

Carolina Henríquez

Hernán Speisky

Italo Chiffelle

Tania Valenzuela

Manuel Araya

Sergio Almonacid

18 February 2020 in Foods

Journal Article

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.

2 January 2023 in Food Reviews International

Journal Article

Nutritional Properties of Fish Bones: Potential Applications in the Food Industry

Alvaro Pérez

Manuel Ruz

Paula García

Paula Jiménez

Pedro Luis Valencia

Sergio Almonacid

Dietary calcium intake below the recommended levels is widespread worldwide. Therefore, there is an urgent need to identify and implement new sources of this nutrient. Fish bones are rich in calcium and bioactive peptides and can be used as ingredients for the manufacture of functional foods or to improve the technological properties of food. Thus, fish bones may be an interesting alternative to traditional sources of calcium, such as dairy products. This review analyzes the available information on processes related to the derivation of calcium from fish bones, including solubilization of hydroxyapatite, reduction of particle size to nanometer range, and addition of calcium-chelating peptides. These processes are highly relevant for obtaining ingredients with a high calcium content, high availability, and adequate sensory properties when added to foods. Thus, fish bone powder has immense potential as a source of bioavailable calcium for food fortification. In addition to the biological and technological considerations, the use of a usually discarded part of fish as a source of bioactive ingredients not only represents an advantage in terms of contributing to waste reduction in food processing but also provides an economic reward.

8 December 2021 in Foods

Journal Article

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

Pedro Luis Valencia

Silvana Valdivia

Suleivys Milagros Nuñez González

Reza Ovissipour

Marlene Pinto

Sergio Almonacid

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.

29 May 2010 in Food and Bioprocess Technology

Journal Article

A Comparative Study of Stout Beer Batch Fermentation Using Free and Microencapsulated Yeasts

Sergio Almonacid

Ana L. Nájera

Manuel E. Young

Ricardo J. Simpson

Cristian Acevedo

12 June 2024 in Foods

Journal Article

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.

About Me

Sergio Almonacid is a food engineer from the Pontifical Catholic University of Valparaiso (PUCV), Chile with an MSc from the Department of Food Science and Technology at Oregon State University, USA, and PhD from the Department of Bioresource Engineering at Oregon State University, USA. Between 1992 and 1998, he worked for the Agroindustrial Department of Fundación Chile, a technology transfer institution that was a pioneer in the modernization of the Chilean food industry (e.g., salmon, winemaking, fruit and vegetable, and seafood industries). In 1998, he joined the Department of Chemical and Environmental Engineering at Universidad Técnica Federico Santa María, Valparaíso, Chile, where he is currently a professor. His research interests are mainly related to thermal and drying processing (technology, modeling, and optimization), and sustainable engineering (use of byproducts from the food processing industry, emphasizing protein hydrolysis and nanosensing technologies for the transformation of byproducts into functional ingredients). He also studies the formulation and process development of final functional food products via drying (e.g., freeze drying, drum drying) and thermal processing technologies. He has produced more than 72 scientific journal publications, 6 books and/or book chapters, and over 130 scientific presentations at international/national symposia and congresses. He has been the principal researcher in 12 projects.

Dr. Sergio Almonacid

Dr. Sergio Almonacid

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About Me