## 1 Introduction  
Pickering emulsions, which contain solid particles as stabilizer, are nowadays used for different applications. Several emulsifiers have been used. such as lecithin and monooleates [1], mono- and diglyceride of fatty acids [2], polymer particles [3], chitin nanocrystals [4], magnetic nanoparticles [5], starch [6; 7], oligosaccharides as \(\alpha\)-cyclodextrinrin [8], and several products from cellulose. Cellulose products have also been used to prepare Pickering emulsions as milled cellulose [9]; cellulose nanofibers (CNF) chemically modified using lauroyl chloride [10]; bacterial cellulose [11]; hydroxypropyl microcellulose [12]; cellulose microfibers (CMF) treated with essential oils [13]; chemically unmodified cellulose nano/microcrystals using different alkanes as the oil phase [14; 15; 16; 17]; and chemically modified cellulose, such as sulfated [10], carboxylated [18], or grafted cellulose nanocrystals [19]. To obtain these products, mechanical treatments, such as homogenization, are used. In most cases, some mechanical, biological, or chemical pretreatment is necessary to reduce the energy consumption in the mechanical process [20; 21]. Several reviews have been published for cellulose product characteristics, their properties, or applications [22; 23; 24; 25]. However, not all pretreatments are acceptable in the food industry due to the toxicity of some chemical agents used. In the food industry, Pickering emulsions using cellulose products as emulsifiers include cellulose nanocrystals chemically modified with ocenyl succinin anhydride [26] or ethyl lauroyl aginate [27] and CMF modified with hydrophilic polymers (cellulose esters/ethers) or pretreated with enzymatical or carboxymethylation pretreatment as emulsifier/stabilizer in whipped toppings, sauces, foams, or bakery products [28; 29]. In this way, cellulose is not digested by human beings, although it can be partially broken down into smaller components for absorption into the bloodstream and is considered as dietary fiber [30]. To the best of our knowledge, there have been few studies related to the use of chemically unmodified CMF in food-grade Pickering emulsions that can substitute unhealthy fats in food products. [PERSON] and [PERSON] [31] studied the stability and the rheology of soy oil-in-water emulsions with low oil content (10%) using chemically unmodified CMF produced from mangosteen rind. [PERSON] et al. [32] studied the synergy of cellulose nanocrystals and CNF without any modification to stabilize edible oil-in-water emulsions with 10% sunflower oil. This paper is focused on the use of chemically unmodified CMF as a stabilizer in emulsions with high oil content, above 20%, and the influence of CMF doses on the stability and rheology of these emulsions. Food manufacturers use the partial hydrogenation of unsaturated fatty acids (UFA) to produce saturated fatty acids (SFA) with more desirable properties, such as increased hardness, greater stability, higher resistance to oxidation, and longer shelf life of vegetable oils. In this process, UFA (with cis configuration in nature) converts some of the cis double bonds into trans bonds by an isomerization reaction, creating trans fatty acids (TFA). TFA are less healthy than SFA and UFA as they decrease HDL cholesterol and increase LDL cholesterol in the blood, increasing the probability of heart disease and sudden cardiac death. As a result, governments and international organizations are making an effort to warn people about TFA and are developing laws to limit the amount of TFA in foods by replacing SFA and TFA with UFA [2; 33; 34; 35]. On the other hand, many organizations have pointed out the importance of meeting future societal needs by promoting the conservation and care of population health through healthy eating [36]. Some alternatives to hydrogenation of UFA have been explored in industries, such as intereesterification or fractionation.