Effect of Extrusion Temperature and Feed Moisture Content on the Microstructural Properties of Rice-Flour Pellets and Their Impact on the Expanded Product

Extrusion can lead to an expanded product or to a slightly expanded pellet, known as a third-generation (3G) snack. In this case, expansion occurs subsequently, in an independent thermal device (e.g., oven), out of the extruded pellet. During both processes, several structural changes occur which are linked to processing conditions, including cooking temperature, screw speed, formulation, and initial moisture content. However, a clear relationship between processing variables and the structure of pellets and expanded products has not yet been identified. Accordingly, this work aimed to study the effect of extrusion temperature (110, 135, and 150 °C) and moisture content (27, 29, and 31%) in rice-flour pellets and their microwave expansion, through a microstructural approach using micro-CT. The results showed that the lowest moisture content (27%) and the highest extrusion temperature (150 °C) led to the highest pellet volume and the highest wall thickness, which in turn led to the highest expansion after microwave heating (50 s, 800 W). Interestingly, no significant differences were observed when analyzing the ratio between the volume of the expanded products and the volume of the pellet (~2.4) when using the different processing conditions.

Catalyzed-Mea conversion of Agro-biomass to paper-pulp: Influence of pulping additives and synergy effect on pulp screened yield

In this research work, the effect of three (3) pulping additives such as polysulfide, Anthraquinone and surfactant used in the monoethanolamine (MEA) pulping of agro-biomass, their possible interactions and synergy effect on pulp screened yield were investigated. The pulping conditions of the digester were adjusted so that the experimental design considered the following factors and levels: 75% MEA charge, 150oC cooking temperature, 90minutes cooking time, 4 to 1Liquor- Biomass ratio. Factor 1: 0, 0.25 and 0.5% Surfactant charge, Factor 2: 0, 2.0 and 4.0% polysulfide charge, Factor 3: 0, 0.25 and 0.5% anthraquinone charge. The Agro-biomass was evaluated in terms of pulp screened yield. Heating time ranged from 5 to 45minutes and maximum cooking time did not exceed 90minutes, liquor biomass ratio was 4 to 1 and Liquor charge was 75% MEA. The yield for MEA with 4% Polysulfide (PS) dosage without the inclusion of Surfactant and Anthraquinone was highest (59.08%) in all the twenty seven (27) experimental runs, but furnished the highest reject (12.26%) and an unimpressive screened yield of 46.82% standing amongst the least possible outcomes. The yield for MEA with 0.25% Anthraquinone (AQ) dosage without the inclusion of Surfactant and Polysulfide furnished a total yield of 50.32%, pulp screened yield of 50.03% with a minimal reject of 0.29 showing to be more efficient than the use of polysulfide. Monoethanolamine (MEA) pulping with 0.5% surfactant (Surf.) dosage without the inclusion of other additives i.e. AQ and PS achieved 51.12% total screened yield with a reject of only 0.33% furnishing the highest pulp screened yield (50.79%) thereby showing more efficiency amongst the three (3) pulping additives investigated in this research study base on single use. However, the result obtained from the combination of the three (3) pulping additives furnished the highest screened yield (52.43) with 4.23% reject in scenario E, experiment No. 15, involving the combination of 0.25% surfactant, 0.25% anthraquinone and 4% polysulfide charge showing the best synergistic effect. Although the highest screened yield (53.04% and the least reject (0.13%) indicating the best possible outcome amongst the entire twenty seven (27) experimental runs came from the combination of 0.25% surfactant and 2% polysulfide charge. If we have to consider the use of surfactant and polysulfide alone, the best possible outcome came from the combination of 0.25% surfactant and 2% polysulfide charge in experiment 20 of scenario G. Analyses of the overall experimental results show that there is considerable advantage and a positive synergy effect in the use of additives in pulping operation.

Effect of Water Temperature and Time during Heating on Mass Loss and Rheology of Cheese Curds

During the manufacturing of mozzarella, cheese curds are heated to the desired stretching temperature traditionally by immersion in water, which influences the curd characteristics before stretching, and consequently the final cheese properties. In this study, cheese curds were immersed in hot water at 60, 70, 80 and 90 °C up to 16 min and the kinetics of mass loss and changes of rheological properties were investigated. The total mass of cooked curds increased up to 10% during the first minute, independent of the temperature, as a consequence of water retention. Fat was the main component lost into the cooking water (<3.5% w/w), while the concentration of protein increased up to 3.4% (w/w) compared to uncooked curds due to the loss of other components. Curds macrostructure during cooking showed that curds fully fuse at 70 °C/4 min; 80 °C/2 min and 90 °C/1 min, while after intensive cooking (>8 min) they lost the ability to fuse as a consequence of protein contraction and fat loss. Storage modulus, representing the curd strength, was dependent on cooking temperature and positively, and linearly, correlated with curd protein content (21.7–24.9%). This work shows the potential to modify curd composition and structure, which will have consequences for further processing and final product properties.

Instrumental and Sensory Characteristics of Commercial Korean Rice Noodles

In this study, the rheological properties of several commercial rice noodle strands were investigated. In the bending test, failure stress decreased as the cooking temperature increased from 80 to 90 °C, and the cooking time increased from 3 to 4 min for higher rice content noodles (>60%). The stress–relaxation test and sensory tests were carried out with bundles of noodles to investigate correlations with the bending test. The modulus of elasticity was higher at 80 than 90 °C. However, no correlation was found between cooking temperature and the rheological properties of lower rice content noodles. In the stress relaxation test, the deviation was larger due to the empty space in the bundle. In the correlation analysis, sensory stickiness was correlated with a modulus of elasticity in the bending test. Comparing the bending and stress–relaxation tests, each instrumental variable showed differences in the rheological properties of rice noodles in strands and bundles. However, the bending test measured with noodle strands seemed to be most suitable as a method of measuring the rheological properties of rice noodles.

Thermal processing reduces PFAS concentrations in blue food – A systematic review and meta-analysis

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and often ingested with food. PFAS exposure in people can have detrimental health consequences. Therefore, reducing PFAS burdens in food items is of great importance to public health. Here, we investigated whether cooking reduces PFAS concentrations in animal-derived food products by synthesizing experimental studies. Further, we examined the moderating effects of the following five variables: cooking time, liquid / food item ratio, cooking temperature, carbon chain length of PFAS and the cooking category (oil-based, water-based &amp; no-liquid cooking). In our systematic review searches (including the grey literature), we obtained 512 effect sizes from 10 relevant studies. These studies exclusively explored changes in PFAS concentrations in cooked seafood and freshwater fish. Our phylogenetically controlled multilevel-meta-analysis has revealed that, on average, cooking reduced PFAS concentrations by 28%, although heterogeneity among effect sizes was very high (I2 = 94.65%). Our five moderators cumulatively explained 36% of the observed heterogeneity. Specifically, an increase in cooking time and liquid / animal tissue ratio, as well as shorter carbon chain length of PFAS (when cooked with oil) were associated with significant reductions in PFAS concentrations. The effects of different ways of cooking depended on the other moderators, while the effect of cooking temperature itself was not significant. Overall, cooking can reduce PFAS concentrations in blue food (seafood and freshwater fish). However, it is important to note that complete PFAS elimination requires unrealistically long cooking times and large liquid / animal tissue ratios. Currently, literature on the impact of cooking of terrestrial animal produce on PFAS concentrations is lacking, which limits the inference and generalisation of our meta-analysis. However, our work represents the first step towards developing guidelines to reduce PFAS in food via cooking exclusively with common kitchen items and techniques.

Comparative assessment of the pulping potentials of soda and mea processes for the development of paper-pulp from sugarcane bagasse

Pulping trials were carried out using MEA and the soda process comparing their pulping potentials. The operating conditions such as the concentration of the cooking liquor (50%, 75%, 100%) for MEA and (10%, 15%, 20%) for NaOH, the maximum cooking temperature (150oC, 160oC, 170oC) and cooking time (60, 90, 120minutes) for both processes were investigated systematically to establish optimal pulping conditions. The agro-biomass used in this investigation is Sugarcane Bagasse viewed as alternative raw material for pulp and paper production. The lignin content of Bagasse (19.5%) was low; indicating that Bagasse should be easier to pulp. The optimum cooking conditions (independent variables) for MEA pulping were 75% MEA concentration, 150oC cooking temperature and 90 minutes cooking time. Excel 2013 was used to analyze the effect of independent variables on yield of bagasse pulp and properties of furnished paper from MEA process in comparison with the Soda process which include tear index, tensile index, burst index and folding endurance with errors less than 15% in all cases. The Kappa number range (12.7-16.9), viscosity (270-870 ml/g) and brightness (62.1-93.2%) of bagasse pulp are appropriate for high-brightness printing and writing papers. The physical properties of furnished paper, tear index (13.4 mN.m2/g), tensile index (71Nm/g), Burst index (4.8 KN/g) and folding endurance (82) recommend the cellulosic pulp from Sugarcane Bagasse obtained from the MEA process for strengthening the virgin fiber in recycled papers and also for developing certain types of printing and packaging papers. Due to the awareness towards the negative impact of kraft mill’s effluent to the environment recently, soda pulping started to regain its popularity among the pulp mills especially non-wood based pulp mills. MEA process is more economically attractive given its high pulp yield, despite the significant increase in chemical demand for bleaching. MEA pulping is a good alternative to soda pulping furnishing high pulp yield with less cooking temperature, i.e. 150oC, thereby saving a considerable amount of energy with less odoriferous pollutants and pollution load associated with the soda process.

Effect of Moisture Distribution Changes Induced by Different Cooking Temperature on Cooking Quality and Texture Properties of Noodles Made from Whole Tartary Buckwheat

While precooking and processing have improved the quality of gluten-free noodles, the effects of different cooking temperatures on their quality—neither gluten-free noodles nor whole Tartary buckwheat noodles—have rarely been clarified. This study investigated the key role of moisture distribution induced by different cooking temperatures in improving the noodle quality of whole Tartary buckwheat. The results showed that cooking temperatures higher than 70 °C led to a sharp increase in cooking loss, flavonoid loss and the rate of broken noodles, as well as a sharp decrease in water absorption. Moreover, the noodles cooked at 70 °C showed the lowest rate of hardness and chewiness and the highest tensile strength of all cooking temperatures from 20 °C to 110 °C. The main positive attribute of noodles cooked at 70 °C might be their high uniform moisture distribution during cooking. Cooking at 70 °C for 12 min was determined as the best condition for the quality improvement of whole Tartary buckwheat noodles. This is the first study to illustrate the importance of cooking temperatures on the quality of Tartary buckwheat noodles. More consideration must also be given to the optimal cooking conditions for different gluten-free noodles made from minor coarse cereals.

NH4OH- KOH Pulping and Single-Stage Bleaching Processes of Banana Pseudostem Waste: A Feasibility Study for Molded Pulp Packaging Use

The NH4OH-KOH pulping was a highly efficient process for extracting banana pseudostem waste (BNW) pulp. Besides, this greener pulping process allowed NH4OH recovery and KOH can be later used as fertilizer, reducing the environmental impact. It was found that the optimal BNW pulping condition was using 8.3 wt% NH4OH and 3.3 wt% KOH at a cooking temperature of 155°C for 1 h, and liquid to solid ratio 6:1. From the results, this process allowed low chemical usage and provided high pulp yield (44%) with a high delignification degree (80%) and low Kappa no. (22). After pulping, the single-stage bleaching of BNW pulp using 8 wt% H2O2 and 1.5 wt% NaOH at 90°C for 1 h was shown to improve the whiteness and brightness of the BNW molded pulp samples to 69.7% and 28.7%ISO (3-fold increase), respectively. As compared to commercial molded pulp food packaging, the present BNW molded pulp exhibited a superior tensile index of 54.3 Nm/g and Young’s modulus of 4.8 GPa.

Paper making and characterization from waste coconut and tofu dregs

Research on paper made from coconut and tofu waste has been carried out using the alkalization method of separation technique, with the optimum composition as follows: NaOH concentration used is 3.0% and cooking temperature is 100 0C and the time required is 90 minutes. The results of the catheterization test of paper made from coconut dregs and tofu have a water content of 3.2%; pH 6.9, pulp content 65.75%; cellulose content 80.22%; lignin content 18.27%. The results of the FT-IR spectrum analysis of coconut pulp and tofu pulp are suitable for use as raw materials for making paper because they contain cellulose fibers. This is indicated by the appearance of the O-H hydroxyl group which is observed at a wavenumber of 3312 cm-1. Based on the SEM results, the surface morphology of the coconut pulp and tofu combination paper shows that the surface structure is the denser the fiber bonds, the smaller the fiber diameter, the better the mechanical properties. The results of the research conclusions explain that, paper made from coconut and tofu waste has met the requirements set by SNI 14-0444-1989. Keywords: Paper, Cellulose, Coconut pulp, Tofu pulp, Lignin