Hydrothermal Cooking Research Articles

Dynamic changes in aroma compounds and precursor substances during rice cooking

Cooking is a key process in forming cooked rice flavor, and more data on aroma compounds should be needed during rice cooking. This paper tracked dynamic changes in aroma compounds, sugars, amino acids, and fatty acids during cooking. After soaking, the content of glucose, fructose, oleic acid, and linoleic acid increased. In the hydrothermal cooking stage, glucose, aspartic acid, glutamic acid, and alanine increased significantly (p < 0.05), while fructose, oleic acid, and linoleic acid first increased and then decreased. In raw rice and soaked rice, alkanes and alkenes were the main volatile compounds, and the content of hydrocarbon compounds decreased in the hydrothermal cooking stage, and many aldehydes, alcohols, ketones, and furan compounds were generated. A total of 28 aroma compounds were sniffed by GC-O-MS, and 13 aroma compounds with OAV >1 were screened out. These results showed that raw rice and soaked rice had similar aroma characteristics and aroma precursor substances that mainly accumulated in the SO10 or ST10 stage, and hydrothermal cooking was the key process of rice aroma formation.

Modification of Physiochemical and Techno-Functional Properties of Stink Bean (Parkia speciosa) by Germination and Hydrothermal Cooking Treatment.

Stink bean, Parkia speciosa, is recognized as a significantly underutilized legume with versatile utility and diverse benefits. However, information on the impact of different processing methods, such as germination and hydrothermal cooking, is scarce on stink beans (SBs). Therefore, the current research aimed to explore the efficacy of germination (G) and hydrothermal cooking (HTC) on the physiochemical properties, proximate composition, techno-functional properties, and antioxidant potential of SB flour. Furthermore, Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were employed to assess structural and morphological changes. The results revealed that the physiochemical properties of SB were significantly enhanced through processing, with more pronounced improvements observed during germination. Additionally, SBG exhibited a significantly higher protein content and lower fat content compared to SBHTC and stink bean raw (SBR). Moreover, techno-functional properties such as color intensity, least gelation concentration, and pasting properties were significantly improved in SBG compared to SBHTC and SBR. FTIR analysis of SBG and SBHTC indicated structural modifications in the lipid, protein, and carbohydrate molecules. FESEM examination revealed morphological changes in SBG and SBHTC when compared to SBR. Importantly, SBG exhibited higher antioxidant activity and total phenolic content in comparison to SBHTC and SBR. Therefore, processed SB flour can be incorporated and utilized in product development, highlighting its potential as a plant-based protein source for protein-rich breakfast bars and cookies.

Dynamic Changes in Volatiles, Soluble Sugars, and Fatty Acids in Glutinous Rice during Cooking.

Cooking is an important process before rice is consumed and constitutes the key process for rice flavor formation. In this paper, dynamic changes in aroma- and sweetness-related compounds were tracked during the entire cooking process (including washing with water, presoaking, and hydrothermal cooking). The volatiles, fatty acids, and soluble sugars in raw rice, washed rice, presoaked rice, and cooked rice were compared. After being washed with water, the total volatiles decreased while aldehydes and unsaturated fatty acids increased. Meanwhile, oligosaccharides decreased and monosaccharides increased. The changes in fatty acids and soluble sugars caused by the presoaking process were similar to those in the water-washing process. However, different changes were observed for volatiles, especially aldehydes and ketone. After hydrothermal cooking, furans, aldehydes, alcohols, and esters increased while hydrocarbons and aromatics decreased. Moreover, all fatty acids increased; among these, oleic acids and linoleic acid increased most. Unlike with washing and presoaking, all soluble sugars except fructose increased after hydrothermal cooking. Principal component analysis showed that cooked rice possessed a volatile profile that was quite different from that of uncooked rice, while washed rice and presoaked rice possessed similar volatile profiles. These results indicated that hydrothermal cooking is the pivotal process for rice flavor formation.

Effect of Hydrothermal Cooking and Germination Treatment on Functional and Physicochemical Properties of Parkia timoriana Bean Flours: An Underexplored Legume Species of Parkia Genera.

The present study was undertaken to analyze the impact of germination (NBG) and hydrothermal cooking (NBHTC) on the nutritional profile and physicochemical, functional and microstructural properties of Nitta bean (Parkia timoriana) (NBR) seeds. Results demonstrated that the highest crude protein and fat content could be found in NBG and NBHTC, whereas the ash content was significantly higher in NBG. Compared to NBHTC and NBR, NBG has higher emulsion capacity and stability, with values determined to be 58.33 ± 1.67 and 63.89 ± 2.67, respectively. In addition, the highest color intensity was also reported for NBG, followed by NBHTC and NBR. Likewise, NBG showed complete gel formation at a lower concentration (12 g/100 mL) than NBR flour (18 g/100 mL). Furthermore, structural changes in the lipid, protein, and carbohydrate molecules of NBG and NBHTC were evidenced by FTIR studies. Morphological changes were noticed in different samples during microscopic observations subjected to germination and hydrothermal treatment. In contrast to NBR and NBHTC, NBG showed the highest total polyphenol content, ORAC antioxidant, and DPPH radical scavenging activity, which demonstrated the potential utilization of Nitta bean flour as a natural plant-based protein source in food security product formulations.

Effect of Hydrothermal Cooking Combined with High-Pressure Homogenization and Enzymatic Hydrolysis on the Solubility and Stability of Peanut Protein at Low pH.

A novel method combining high-pressure homogenization with enzymatic hydrolysis and hydrothermal cooking (HTC) was applied in this study to modify the structure of peanut protein, thus improving its physicochemical properties. Results showed that after combined modification, the solubility of peanut protein at a pH range of 2–10 was significantly improved. Moreover, the Turbiscan stability index of modified protein in the acidic solution was significantly decreased, indicating its excellent stability in low pH. From SDS-PAGE (Sodium Dodecyl Sulfate PolyAcrylamide Gel Electrophoresis), the high molecular weight fractions in modified protein were dissociated and the low molecular weight fractions increased. The combined modification decreased the particle size of peanut protein from 74.82 to 21.74 μm and shifted the isoelectric point to a lower pH. The improvement of solubility was also confirmed from the decrease in surface hydrophobicity and changes in secondary structure. This study provides some references on the modification of plant protein as well as addresses the possibility of applying peanut protein to acidic beverages.

Glycation of rice protein and d-xylose pretreated through hydrothermal cooking-assisted high hydrostatic pressure: Focus on the structural and functional properties

Rice protein (RP) and d-xylose (Xe) glycosylation reaction products were prepared by hydrothermal cooking (HTC)-assisted high hydrostatic pressure (HHP) under different pressures (100–300 MPa). The structural and functional properties of RP, RP-XeH (only by HTC treatment), and RP-XeHP (by HTC-assisted HHP treatment) were investigated. The results revealed that the grafting degree and solubility of RP-XeHP increased with increasing pressure. Moreover, the intrinsic fluorescence intensity of RP-XeHP decreased, whereas the sugar fluorescence spectroscopy increased. SDS–PAGE revealed that soluble aggregates were formed by the covalent interactions between glutelin and d-xylose in RP-XeHP, and the amino acids that participate in the reaction mainly include Cys, Tyr, Lys, and Arg. FTIR spectral analysis further revealed that the secondary structure changed. Moderate pressure (100 MPa) strengthened the emulsifying properties of RP-XeHP, whereas high pressure (300 MPa) had a negative effect on the emulsifying properties. Furthermore, RP-XeHP exhibited outstanding antioxidant activity. This study provides new insight into RP glycated by HTC-assisted HHP treatment.

Energy value and bioactive proteins of inulin‐enriched tofu produced by hydrothermal process with chymosin‐pepsin rennet

SummaryNutritional properties of inulin‐enriched tofu obtained after hydrothermal cooking of soymilk, using chymosin‐pepsin rennet and inulin as a functional ingredient, were assessed. This procedure significantly differs from the traditional one. The residual activity (rTIA) of trypsin inhibitors (TIs) and lectins, content of proteins, carbohydrates, fats and their energy values (EV) were suitable for human nutrition. Inulin‐enriched tofu was characterised with low rTIA (3.08–5.71%) and TIs content of 3.62–18.99%. Content of Kunitz and Bowman‐Birk TIs as well as total TIs content (r = 0.98) in tofu were strongly correlated with tofu protein content. Content of Bowman‐Birk polymeric forms (3.11–5.36%) was higher than Bowman‐Birk monomeric forms (0.51–2.31%) in inulin‐enriched tofu. Low urease activity (0.60–1.78%) indicated that soybean was heated adequately to inactivate TIs. Increasing content of inulin did not increase tofu EV (˜18 kJ per g tofu). The proximate composition of inulin‐enriched tofu, advantageous rTIA and a very low EV qualifies this product for human nutrition.

Influence of thermal processing on the characteristics and chemical profile of ora-pro-nobis by PS/MS paper spray

This work aimed to evaluate the influence of dry and wet heat processing on the antioxidant profile and antioxidant activity in ora-pro-nobis leaves. The leaves were collected, washed, and separated into three groups for the treatments: application of moist heat (hydrothermal cooking at 100 ºC / 4 minutes), application of dry heat (70 ºC / 8 hours), and control (raw material). The characteristics were evaluated: total soluble solids (SST), total solids (ST), pH, phenolic compounds (CPT), flavonoids (FT), anthocyanins (AT), antioxidant activity (AA). To identify the chemical profile and the chemical profile, fingerprints were obtained using PS / MS paper spray. The content of SST and ST decreased with moist heat. The CFT content increased with wet heat (12.43 ± 0.98) and decreased with dry heat (4.25 ± 0.93 g EAG 100 g-1). There was a decrease in the FT and AT content in the leaves processed with dry heat (132.67 ± 20.28 mg 100 g-1 and 19.70 ± 3.34 mg CG 100 g-1, respectively). AA decreased in both processes, which was higher in ora-pro-nobis leaves processed with dry heat (0.82 ± 0.0033 µmol ET g-1). 26 phenolic compounds were identified in the ora-pro-nob leaves by paper spray. The chemical profile, except for the substances 4,5-dimethyl-2,6-octadiene and methyl ester linolenic acid was not affected by thermal processing. Knowing the effect of food processing is important to understand the behavior of compounds that act beneficially on human health.

Protein composition and textural properties of inulin-enriched tofu produced by hydrothermal process

Tofu protein composition changes induced by a pilot plant processing method involving hydrothermal cooking, commercial rennet as coagulant and inulin as functional ingredient were assessed. Glycoproteins (γ-, β-conglycinin) were firmly bound to the matrix of the obtained gels. Extractable proteins of inulin-enriched tofu were with mainly basic 7S-globulin, and polypeptides of glycinin. Polypeptides A1,2,4 and B1,2,4 were found in higher concentrations in protein extracts of tofu than other 11S polypeptides. Tofu was characterized by high total (417.6–556.5 g/kg) and extractable soluble (155.3–367.5 g/kg) protein content, good protein extractability (37.2–68.6%), both total protein (52–69%) and soluble protein (50–76%) recovery. Increasing concentrations of inulin proportionally improved tofu hardness (6.23–8.98 N/cm2) contributing to the uniformity of gel microstructures. Inulin played an important role in incorporating β- and γ-conglycinins into the gel matrix and by increasing the concentration of inulin in soymilk before gelation, the content of extractable soluble proteins, protein extractability and soluble protein recovery of produced tofu were also proportionally increased. For all tested sensory attributes the grades were increased with increasing inulin content in the samples. Under the applied production method, protein composition and proportion of inulin had important roles in defining tofu quality.

Physiochemical and Conformational Properties of Soluble aggregates from Soy Protein Isolates mediated by Hydrothermal cooking: A comparative study with moisture heat treatment

Physiochemical and Conformational Properties of Soluble aggregates from Soy Protein Isolates mediated by Hydrothermal cooking: A comparative study with moisture heat treatment

The influence of soybean genotypes and HTC processing method on trypsin inhibitor activity of soymilk

Kunitz inhibitor (KTI) and Bowman-Birk trypsin inhibitor (BBI) are inhibitors of digestive enzymes in raw soybeans. Due to their antinutritive properties in the active state, their inactivation by heat treatment is commonly used. Soymilk is a turbid and stable colloidal solution, obtained by thermal treatment of soybean. In this study soymilk was made on a pilot-plant scale from six soybean cultivars using hydrothermal cooking (HTC) as the production method. This procedure is significantly different from the traditional one. The aim of this investigation was to evaluate the impact of the HTC processing for soymilk production and different soybean genotypes on trypsin inhibitor content and activity. Obtained soymilk contained BBI in trace amounts, in the BBI-polymeric forms. The BBI monomeric forms were not detected. The soymilk of the investigated soybean genotypes had very similar KTI levels (2.34-2.99%). Results have suggested that the soybean genotype does not have substantial effects on the levels of KTI, as well as on the value of residual trypsin inhibitor activity (rTIA). The total content of TI and rTIA showed a strong dependence (r=0.91; p&lt;0.05). HTC-soymilk rTIA was &lt;20% (7.15-19.89%). These results have indicated that HTC processed soymilk is applicable for human consumption.

Preparation and characterisation of soya milk enriched with isoflavone aglycone fermented by lactic acid bacteria combined with hydrothermal cooking pretreatment

SummaryA fermented soya milk (FSM) enriched with isoflavone aglycone (FSM‐SPIA) was prepared from heated soya protein isolate (SPI)‐isoflavone complex. After 48 h of fermentation, FSM‐SPIA contained higher contents of living bacteria, free amino acids and aglycone compared with the FSM of SPI (FSM‐SPI) and the FSM of SPI‐isoflavone complex (FSM‐Mix). In the in‐vitro digestion experiment, FSM‐SPIA showed higher antioxidant capacity and isoflavones (ISO) bioavailability than FSM‐SPI and FSM‐Mix. This was likely due to the soya milk containing a higher level of amino acid, peptides and the presence of soya bean isoflavone. The improved protein digestibility, the interaction and binding ability between proteins and ISO may affect the properties of the protein and the fermented products. The FSM enriched with isoflavone aglycone can be used as a functional fermented drink, as well as an auxiliary food for menopausal women during a specific pathological period.

Influence of Soy Protein Isolate Prepared by Phosphate‐Assisted Hydrothermal Cooking on the Gelation of Myofibrillar Protein

AbstractThe poor solubility and functionalities of soy protein concentrate (SPC) limits its utilization in meat products. Phosphate‐assisted hydrothermal cooking (HTC) was applied to refunctionalize SPC in this work. The resultant soy protein isolate (SPI) was used as an ingredient for improving the gelation of porcine myofibrillar protein (MP) which was induced by microbial transglutaminase (MTGase). The addition of sodium tripolyphosphate (STPP) enhanced the refunctionalization efficiency of HTC and increased the phosphorus content in the obtained SPI. Dynamic rheological analysis indicated that this SPI itself could not form a gel with the help of MTGase. However, the SEM observation revealed that the presence of this SPI strengthened the gel network of MP and made it become denser and more ordered. As a result, the mechanical properties and water holding capacity of the MP gel were significantly improved by this SPI prepared by phosphate‐assisted HTC.

Mineral elements, lipoxygenase activity, and antioxidant capacity of okara as a byproduct in hydrothermal processing of soy milk.

Minerals and antioxidative capacity of raw okara that was obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. Lipoxygenase (Lox), an enzyme deteriorating the sensory characteristics of okara, was also investigated. All genotypes had very similar concentrations of Lox (4.32-5.62%). Compared to raw soybeans, the applied HTC significantly reduced Lox content in okara (0.54-0.19%) and lowered its activity to 0.004-0.007 μmol g(-1) min (-1). Correlation between the content of Lox in soybeans and that in okara (r = 0.21;p < 0.05) was not registered. This indicates that the content of this enzyme in okara depended much more on the technological process than on soybean genotype. Very strong correlation (r = 0.99; p < 0.05) between okara Lox content and its activity was found. The most abundant minerals in raw okara were potassium (1.04-1.21 g/100g), phosphorus (0.45-0.50 g/100 g), calcium (0.26-0.39 g/100 g), and iron (5.45-10.95 mg/100 g). A very high antioxidant capacity (19.06-29.36 mmol Trolox kg(-1)) contributes to the nutritional value of raw okara.

THE INFLUENCE OF SOUS-VIDE TREATMENT ON THE FORM OF MOISTURE IN LARGE-VEGETABLE MEAT SYSTEMS

Abstract The current development of the catering industry is due to the improvement of the processes of heat cooking of raw materials. One such area is the use of low-temperature hydrothermal cooking food, pre-vacuum-packed in heat-resistant polymer film. In cooking, spread a combination of rice, chicken and vegetable ingredients: onions and carrots, which allows you to get a dish with high consumer properties. During the study, it was determined the amount of moisture needed to reach the desired consistency of the mixture components to increase the yield of finished products, while providing maximum storage periods. The results show that the addition of water in amounts exceeding 3.0% of the total weight of food leads to an increase in the mass fraction of free moisture

Bioactive Proteins and Energy Value of Okara as a Byproduct in Hydrothermal Processing of Soy Milk

The nutritional properties of raw okara obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. The composition and residual activity (rTIA) of trypsin inhibitors (TIs), contents of lectin, proteins, fats, and carbohydrates, and energy values (EV) were correlated with the respective physicochemical properties of soybean and okara. Kunitz (KTI) and Bowman-Birk (BBI) TIs both comprised okara rTIA. TIs content was higher in okara (5.19-14.40%) than in soybean (3.10-12.17%), which additionally enriched okara by cysteine. Contents of KTI (r = 1.00;p < 0.05) and BBI (r = 0.89;p < 0.05) as well as BBI monomeric (r = 0.89;p < 0.05) and polymeric forms (r = 0.95;p < 0.05) in okara and in soybean were strongly correlated. Low urease index activity indicated that okara was heated adequately to inactivate antinutritional factors. The proximate composition of raw okara, advantageous rTIA, and a very low EV (2.74-3.78 kJ/g) qualify this byproduct for potential application in food preparation as a functional ingredient in dietary products.

Effect of incorporating hydrothermal, kilned and defatted oats on antioxidant and chapatti making properties of wheat flour

Oats were subjected to treatments like defatting, hydrothermal cooking and kilning, milled into flour and then the control and treated flours were incorporated into wheat flour at 25% and 50% levels and chapatti making behaviour and antioxidant properties were studied. The treatments significantly affected the antioxidant properties of oats. Incorporating oat flours to wheat increased total phenolic content but lowered the antioxidant activity however both were decreased significantly upon baking. The reducing power of the oat blended flour was higher than the wheat flours and ranged from 8.0 to 15.5μmol AAE/g and was further increased upon baking. The metal chelating activity of flour blends varied from 62.0% to 73.8% and further increased upon baking. After baking the total flavonoid content was lowered and ranged from 308 to 389μg CE/g. The non-enzymatic browning index significantly increased up to 27.6% upon baking.

Stability and bioaccessibility of different forms of carotenoids and vitamin A during in vitro digestion

Vitamin A deficiency is a public health issue in developing countries and promoting dietary carotenoids as precursors is a promising strategy. However, carotenoids present in numerous fruits and vegetables are unstable and poorly bioaccessible. This study evaluated these two parameters during in vitro digestion of carotenoids and retinoids from carrot juice, raw and cooked spinach, micronutrient-fortified flour and standards without food matrix. Standards were unstable whereas vitamin A from fortified flour and native food carotenoids were generally better protected by the food matrix (30–100% remaining versus 7–30% for standards). Hydrothermal cooking did not influence spinach carotenoid digestive stability but decreased their contents, phenomenon compensated by a significantly better micellarisation from 15-fold for β-carotene to 72-fold for lutein. Finally, carrot juice provided the greatest amount of bioaccessible provitamin A with 1850μg/100g dry matter (DM) versus 790 and 80μg/100g DM in cooked and raw spinach, respectively.

Composition of Proteins in Okara as a Byproduct in Hydrothermal Processing of Soy Milk

Protein quality, based on its subunit composition, in okara obtained as a byproduct during hydrothermal cooking of soy milk was assessed. The composition of 7S and 11S protein fractions was correlated with the physicochemical properties of protein in okara produced from six soybean varieties. The basic 7S globulin (Bg7S) and 11S protein were two main proteins in okara. Investigated soybean genotypes produced okara with mainly acidic A(5) and basic B(1,2,4) polypeptides of 11S proteins. Soybean 11S content was not an indicator of okara protein recovery or extractability. Of all tested relationships, extractable soluble protein content of okara was influenced only by soybean Bg7S (r = 0.86; p < 0.05) and its light subunit contents (r = 0.93; p < 0.05). Okara protein recovery depended on Bg7S heavy subunit content in soybeans (r = 0.81; p < 0.05). The high quantity of vegetable protein in okara (around 35%) and very high protein extractability (around 85%) qualify this byproduct for potential application in food preparation as a functional ingredient.

Preparation and characterization of protein from heat-stabilized rice bran using hydrothermal cooking combined with amylase pretreatment

Hydrothermal cooking (HTC) combined with amylase pretreatment (AP) was used to improve protein extraction from heat-stabilized rice bran. The physicochemical and emulsifying properties of rice bran protein isolate (RPI) were evaluated. Depending on HTC temperature (120 and 150 °C), HTC alone significantly increased extraction yield, while protein purity was decreased. In contrast, HTC combined with AP significantly improved both extraction yield and protein purity (about 45–50% and 72–74%, respectively). The AP avoided the co-precipitation of gelatinized starch during the acidic precipitation. Electrophoresis and size exclusion chromatography profiles indicated that HTC led to the dissociation of insoluble protein aggregates in rice bran, with subsequent increase of soluble aggregates in RPI, linked by non-covalent (e.g., hydrophobic interaction) and covalent bonds (disulfide bond). This result was evidenced by the increased disulfide bond contents and surface hydrophobicity of RPI. In addition, HTC-prepared RPI exhibited excellent emulsifying property.