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Drying of Agricultural Crops
Published in Guangnan Chen, Advances in Agricultural Machinery and Technologies, 2018
D. M. C. C. Gunathilake, D. P. Senanayaka, G. Adiletta, Wiji Senadeera
Sulfites were accepted as a safe additive (generally recognized as safe) until its allergenic reaction was observed in sensitive people. If more than the permitted levels are used, it can be allergenic, causing reactions like nettle rash, angio-neurotic edema, and anaphylactic shock in ordinary individuals. Due to this, consumers tend to avoid meta-bisulfite. Furthermore, blanching has been considered to be one of the most important pretreatment technologies. The blanching pretreatment is used to inactivate the enzymes responsible for producing off flavors and unpleasant odor, maintain the freshness color, stabilize the texture and nutritional quality, expel air between the cells, and destroy the microorganisms to some extent.
Control of the Pulp and Paper Making Process
Published in William S. Levine, Control System Applications, 2018
Chemical pulping can be divided into two main processes, sulfite and Kraft. The sulfite process is an acid based cooking process, whose use is in decline. The Kraft process is an alkali-based process in which the active chemicals are fully recycled in the Kraft liquor cycle. The Kraft process itself consists of eight individual unit operations. It starts with wood chips being fed to a digester house (unit process with 50 to 300 control loops) in which the chips are fed to a digester and impregnated with white cooking liquor (a solution of NaOH and Na2S), and “cooked” at about 175°C for about an hour. In this process the lignin and hemicellulose are dissolved. The spent cooking liquor is then extracted and the pulp is “blown” into the “blow” tank. Modern digesters are continuous vertical columns, with the chips descending down the column. The impregnation, cooking, and extraction processes take about three hours or so. Some digester houses use batch digesters instead, with 6 to 20 batch digesters. From the blow tank the pulp is pumped to the brown stock washers (unit process with 20 to 200 control loops), in which the pulp is washed in a multistage countercurrent washing process to remove the spent cooking liquor, including the dissolved organic compounds (lignin, hemicellulose) and the spent sodium compounds which must be removed from the pulp stream and reused. The two output streams consist of: washed pulp (which goes to the bleach plant for bleaching or to the paper machines if bleaching is not required) and the spent liquor which is called black liquor and is returned to the Kraft liquor cycle.
New analytical methods for the determination of sulfur species with microextraction techniques: a review
Published in Journal of Sulfur Chemistry, 2022
Arina Skok, Yaroslav Bazel, Andriy Vishnikin
Sulfur dioxide (SO2) plays a significant role in the food industry. It is added to wines for several reasons: it is powerful antimicrobial negotiator and an effective antioxidant; it also binds some compounds that can spoil wines, such as aldehydes and ketones. Adding sulfite to different food and beverages prevents enzymatic oxidation, the browning reaction and microbial spoilage [3]. Small amounts of sulfites can appear in different food and beverages due to natural fermentation processes. At the same time, high concentrations of sulfite can cause serious asthmatic or allergic reactions.
Reactions Involved in Phenolics Degradation from Sugarcane Juice Treated by Ozone
Published in Ozone: Science & Engineering, 2019
Juliana A. S. Sartori, Célio F. Figueiredo Angolini, Marcos N. Eberlin, Claudio L. Aguiar
During the production of white crystal sugar, sulphitation is commonly applied for color reduction (Payne 2010). Sulphitation presents a disadvantage related to sulfite residue in the final product. Sulfite has been found to be harmful to human health, and studies have shown that people who are sensitive to their intake, have symptoms, such as chest congestion, cough, throat discomfort, hypotension and contact dermatitis, and for people with asthma, it may induce episodes of asthma or bronchospasm (Machado 2008; Papazian 2017).
A novel and improved solar drying system appropriate for smallholder farmers
Published in Drying Technology, 2021
Andrew G. Watson, Salko Aleckovic, Rajeev Nallamothu
Currently, sulfur dioxide is used as an antioxidant pretreatment to prevent browning reactions, loss of flavor and vitamins and to prevent microbial growth in the drying of many types of fruit. Food labeling regulations in developed countries demand that the sulfite be identified as an ingredient on the label. Many consumers avoid purchasing dry fruit which contains sulfites. The SBD might be able to deliver some of the benefits which accrue from sulfur dioxide treatment without adding sulfite residues.