Production of Gracilaria powder

Introduction

A large percentage of the population in thePhilippines suffers from one or more forms ofmalnutrition including micronutrient deficiencies.Among Filipino children, the four major deficiencydisorders are protein-energy malnutrition, iodinedeficiency disorder, Vitamin A deficiency, and irondeficiency. According to the news article issued by theInternational Council for Control of Iodine DeficiencyDisorder (ICCIDD) on May 2013, despite the ASINLaw which mandated the addition of iodine to all saltand other food products, endemic goiter has still beenrecognized in most parts of the country and 50,000Filipino newborns have mental problems due toIodine deficiency. Therefore, it is necessary to findmore specific and focused strategies for vulnerablegroups with iodine deficiency to eradicate relateddisorders even with adequate iodine nutrition.

Seaweed is a macroalgae with an increasingeconomic value on the global market. Recently, theuse of seaweed is growing in popularity in the foodindustry to produce nutritious and useful foods dueto its richness in polysaccharides, minerals, fiber,protein, and omega-3 fatty acids. Additionally,seaweed is a source of hydrocolloids, which aretypically used in the processing of a variety of foodproducts like sauces, ice cream, and soup as athickening agent, gelling agent, emulsifier, andstabilizer (Hamid et al., 2020).

In addition, Seaweeds are also a great source ofdietary fiber. Dietary fiber consists of two fractions:soluble and insoluble, and its properties are mainlydetermined by the proportion of these two fractions.Thus, soluble fiber is characterized by its ability toform viscous gels, in contact with water, in theintestinal tract. Insoluble fiber does not form gels incontact with water but can retain water in itsstructural matrix, producing an increase in fecal massthat accelerates intestinal transit. These differences inthe behavior of the fibers in the intestinal transitresult in different properties. Insoluble fiber issparsely fermented and has a marked laxative andintestinal regulating effect, while soluble fiber isfermented in high proportion, and its main propertiesare related to the decrease of cholesterol and glucosein the blood and the development of intestinalmicrobiota (Peñalver et al., 2020). Finally, the ratioof fiber soluble/insoluble (S/I) is higher in seaweedsthan in terrestrial vegetables, with an average contentof 24.5 g/100 g for soluble fiber and 21.8 g/100 g forinsoluble fiber (Peñalver et al., 2020).

Furthermore, Seaweeds are widely used for foodconsumption by humans and domesticated animals, ithas globally displayed a substantial upsurge over theyears. It has consistently increased from 1990 to 2018and registered a total of 32.9 million metric tons in2018 from 5.05 million metric tons in 1990, resultingin a six-fold growth (FAOSTAT, 2021). In thePhilippines, emerging technologies in seaweedprocessing are becoming more popular. But eventhough there are more and more studies on seaweedsbeing done around the world, little is known aboutthe microbiological makeup of the edible seaweeds inthe Philippines. In the practice of eating seaweedfresh and raw, it is important to examine itsmicrobiological aspect as it may contain fecal andother human pathogens (Besagas and Gamolo, 2018).In connection to Organic Agriculture Act of 2010(Republic Act No. 10068) as amended by RepublicAct No. 11511 in 2021 to "promote, propagate, developfurther and implement the practice of organicagriculture.", that increases farm productivity andfarmers' incomes, encourage the participation ofindigenous organic farmers in promoting theirsustainable practices, and protect the health offarmers, consumers and the public among others(Cabrera and Waguey, 2023), the Gracilaria in thePhilippines specifically from the coastal area ofRabon, Rosario, La Union is naturally grown andabundant.

 As years passed by, according to the FAO GlobefishResearch Programme, dried seaweed productscurrently completely dominate the market. Seaweedshave recently become more widespread in newmarkets and introduced as an ingredient in severalnew products in the US and European markets, and these alternative methods of drying are gainingpopularity (Lovdal et al., 2021). 

According to a study conducted by Colorado StateUniversity, Sulfur and sulfite compounds have beenused for centuries to prevent discoloration and reducespoilage during the preparation, dehydration, storage,and distribution of many foods. However, sulfitesmay initiate asthmatic reactions in some people,especially those with asthma. As a result, the Foodand Drug Administration (FDA) has banned the useof sulfites on fresh fruits and vegetables for sale orserved raw to consumers. They are still used as anantimicrobial agent and to help preserve the color ofsome dried fruit products. Sodium metabisulfite isoften available at pharmacies or where wine-makingsupplies are sold. In using sodium metabisulphite asan antimicrobial agent, stir 1 tablespoon (21 grams) ofsodium metabisulfite into one quart (1000 milliliters)of cold water. Allow the produce to be soaked for 10minutes, and then remove with a slotted spoon, drainwell, and dehydrate.

Due to health and safety concerns, do not useburning sulfur to pretreat fruits for drying. 1.5g ofsodium metabisulphite dissolved in 1 liter of waterwill give 1000ppm (0.1%) SO2. The most practicalway to make a sulfite solution is to prepare a stocksolution of 8,000 ppm (0.8%). This is done bydissolving 12g (2.5 level teaspoons) of sodiummetabisulphite in 1 liter of water. The stock solutioncan be diluted by adding extra water to give weakersolutions (FAO, 2019).

Also, according to an article published by PubMed in2014, sodium metabisulphite is used as anantioxidant agent in many pharmaceuticalformulations. It is extensively used as a foodpreservative and disinfectant.

It was also proven as an anti-microbial agent inshrimp. Which one study conducted they dipped theshrimp into 1.25% sodium metabisulphite solution(1.5 kg/100 liters) for 1 minute with moderateagitation followed by draining. This study hasdemonstrated the effectiveness of sodiummetabisulphite as an agent in delaying melanosisdevelopment in shrimp. Its antimicrobial effect wasconfirmed. 

According to the Guidelines for the Use of ChlorineBleach as a Sanitizer in Food Processing Operationsby Oklahoma State University (2016), Chlorine bleachcan be a very effective method of killing undesirablemicroorganisms Chlorine bleach solutions may beused for sanitizing raw fruits and vegetables duringthe washing or peeling process. The federalregulations that apply differ slightly from those forsanitizing solutions given above. The Code of FederalRegulations of the US Food and Drug Administration(21 CFR Part 173) specifies two conditions for thepermitted use of hypochlorite solutions in washingproduce: (a) the concentration of sanitizer in the washwater must not exceed 2000 ppm, (b) the producemust be rinsed with potable water following thechlorine treatment. Most operations, unless theproduce is very dirty, will not need a sanitizerconcentration greater than 200 ppm total chlorine toachieve the desired sanitizing effect. Contact times ofone minute or greater are typically sufficient toachieve a thorough kill. 

Meanwhile, the Drying method is used to inhibit allmicrobial growth including yeast and mold, andaerobic plate count (APC)-also known as the standardplate count, aerobic mesophilic count, total platecount, or aerobic colony count, a measurement of thenumber of microorganisms that can grow aerobicallyat mesophilic temperatures (Salami et al., 2022). Thedrying method is used to reduce the water activity(Aw) to 0.6 or below, while bacteria of relevance areinhibited at much higher Aw. Determination of theoptimal Aw and moisture content is thereforeessential. The surface-to-volume ratio is very high formost seaweeds and the drying time is relatively shortwhich makes it feasible to dry at low temperatures(<< 60 °C) without risking microbial growth duringdrying. Typical low-temperature drying methods aresun drying and drying with dehumidified air but mayalso be achieved by electromagnetic drying by microwaves or radio frequency. The latter may also beused for high temperature drying alone or incombination with hot air drying, infrared drying, oralternatively by superheated steam drying. Thesehigh-temperature drying methods may be designed toinactivate both bacteria and spores of bacteria. Thismay be of interest when the dried seaweeds areintended for use as ingredients in moist foodsintended to have a shelf life after the addition of theseaweeds (Lovdal et al., 2021).