Formulation of carotene-rich chocolate spread using red palm oil

Chocolate spread is a chocolate food product used to flavor bakery products such as spread on bread. Chocolate spread is made using oil or fat with good spreadability, so this product is easily spread on bread. Red palm oil (RPO) can be applied to chocolate spreads because it can be a source of fat and carotene. In this research, the chocolate spread was made by adding virgin red palm oil from (VRPO) and (RPO), respectively 2, 4, and 6% of the dough ingredients. As a control, the formulation was carried out without adding RPO. The results indicate that VRPO and RPO can produce carotene-rich chocolate spread. The results of the organoleptic test showed that VRPO as much as 2% of the dough ingredient was preferred by the panelists (closer to the control formula). The product with this formula has a particle size of 0.09 mm, a fat-melting point of 29.5 °C, and a fat carotene content of 34.61 ppm.


Introduction
Chocolate is a food product that has a specific taste, texture, and aroma [1,2].Chocolate can generate various stimuli that activate pleasure during consumption [3].It is known that cocoa contains polyphenolic compounds [4,5], which are very good for health.To increase the nutrition of chocolate and its derivatives, the addition of bioactive ingredients from other sources can also be done.Ramya and Bhasker (2018) developed a chocolate formula filled with lemon marmalade [3].Praseptiangga et al. (2018) developed dark chocolate with the addition of cinnamon powder [6].
Chocolate is made in liquid, paste, or block form, or is used as a flavoring agent in other foods [1].Chocolate spread is a processed chocolate product in the form of a paste mostly used as a spread for bread and pastries.Chocolate spread is made by mixing oil or fat, sugar, cocoa powder, milk powder, salt, and emulsifier.Matondang et al., (2014) made Barangan banana peel chocolate spread as an alternative to functional food products [7].The oil used in the manufacture of chocolate spread generally has good spreadability so that it can be easily rubbed into food products.Cocoa butter is a fat that is commonly used in the manufacture of chocolate which is solid at room temperature so it has low spreadability.This is related to cocoa butter's melting point, which ranges from 32-35 °C [8], and the high solid fat content.For this reason, cocoa butter fat can be mixed with other vegetable oils to obtain fat that has the desired spreadability.
Palm oil is widely used for food products.This is due to palm oil's unique characteristics, namely, balanced saturated and unsaturated fatty acids, which make it semi-solid at room temperature [9].In addition, palm oil can be separated into solid (stearin) and liquid (olein) fractions.Each of these fractions has different characteristics so that they can be applied as fat for products with certain desired characteristics [10].Palm oil has also been widely used as a fat substitute for cocoa butter which is known as cocoa butter equivalent (CBE) which is applied in the manufacture of chocolate [8].In addition, palm oil fractions can also be used as fat for the manufacture of margarine for spreads in bakery products.Margarine is also a product that has good spreadability, making it easy to spread on bread.Hasibuan et al. (2022) made chocolate spread from palm oil fraction blends [11].
Red palm oil (RPO) contains high carotene (as pro-vitamin A) which is beneficial for health.Carotene functions to reduce free radicals and can reduce deficiency of vitamin A, as a food supplement [12].Utilization of RPO in chocolate spread production reduce cocoa butter (which is solid at room temperature and relatively expensive).In addition, the resulting chocolate spread product can be used as a functional food that can help reduce KVA.El-Hadad et al. (2011) and Kumar et al. (2016) formulated chocolate spread using the red palm olein fraction to replace butterfat [13,14].The addition of RPO can affect the sensory value of chocolate spread because RPO has a reddish color and a distinctive odor.Therefore, this research was conducted to develop a formula for carotene-rich chocolate spread by adding RPO which has a sensory profile that is liked by consumers.

Materials
The ingredients used are virgin red palm oil (VRPO) which is extracted directly using a conventional method from fresh fruit bunches and neutralized and deodorized of crude palm oil produced from palm oil mills (RPO) which is processed at Science Techno House-Oil Palm Science Techno Park (OPSTP), Indonesian Oil Palm Research Institute.Cocoa butter and cocoa powder from the Indonesian Coffee and Cocoa Research Institute, Jember.Refined bleached deodorized palm oil (RBDPO) is obtained from OPSTP.Super olein is obtained from supermarkets in Medan City.Sugar, salt, powdered milk, lecithin, and vanilla were obtained from a bakery in Medan City.The materials used for analysis were obtained from local E-Merck suppliers.

Production of Chocolate Spread
Production of the chocolate spread was made using the dough formula as presented in Table 1.As much as 1 kg of the dough ingredients were mixed and mashed using a combination of conching and ball mill tool at 50 ºC adopting the procedure from Hasibuan (2015) [15].The initial stage is mixing cocoa butter, RBDPO, super olein, and VRPO or RPO.Then, cocoa powder, sugar, milk powder, salt, and lecithin are added to the fat in sequence.Vanilla is added 30 minutes before the grinding process is complete.The process of smoothing the dough ingredients was carried out for 7 hours.After the time has elapsed, the quality of the chocolate spread product was analyzed including particle size, fat melting point, fat carotene content, oil stability during storage, and organoleptic tests.

Quality Analysis
Particle size (fineness) was determined by placing a chocolate sample (1 g of chocolate spread mixed with 5 g of palm olein and homogenized with stirring for 15 minutes using a magnetic stirrer at 250 rpm) as much as one drop in the Thickness Gauge (Mitutoyo, Japan).The particle size is read according to the tool designation.The oil stability during storage was determined by placing the chocolate spread into a glass tube and measuring the height of the product in the tube.The product in a glass tube was stored at room temperature (28-30 °C) and the oil measurements were observed separately from the product for 1 month.
Melting point and carotene content in fat were determined after extracting fat from chocolate spread by the soxhletation method using n-hexane solvent.Fat's melting point and carotene content were determined using the standard MPOB Test method [16].
The organoleptic test of the chocolate spread was carried out by a hedonic test.The hedonic test is a preference test by asking the panelist's personal opinions about their level of preference for the chocolate spread.In the hedonic test, the untrained panelists (college student) used were somewhat trained panelists of 30 people.The parameters used were taste, color, texture, aroma, and appearance with acceptance levels of 1 (dislike), 2 (did like less), 3 (fairly like), 4 (like), and 5 (very like).

Physicochemical Properties of Chocolate Spread
Chocolate spread is made by grinding the dough ingredients using conching and ball mill refiner [15].In addition to reducing the dough ingredients to smaller sizes, the refining process also mixes the dough ingredients.The fat will coat the sugar, cocoa powder, and milk particles.The finer the particle size, the more perfect the fat coats the other dough particles.The particle size of the chocolate spread is 0.07-0.10mm (Table 2).The particle size tends to be larger than the chocolate bar reported by Hasibuan (2015) which is 0.0175 mm.Chocolate with a particle size > 0.035 mm will feel rough in the mouth [17].
The particle size of the chocolate spread in this study tends to be high because the refining process time is only 7 hours.The chocolate spread will be applied as a spread on bread.Hasibuan et al. (2022) reported that chocolate spread with a low particle size was unnecessary because the chocolate spread was eaten together with bread.In addition, the short processing time is expected to minimize the degradation of carotene compounds.This is because carotene is easily degraded by heat.However, the acceptance of particle size varies by each consumer.The conching process time can be extended to produce a finer particle size.Winkler (2014) revealed that the conching process needs several hours and temperatures from 50-90 °C [18].Storage of chocolate spread at room temperature 28-32 °C for 1 month shows that there is no separation of oil from the mixture (does not cause oily) (Table 2).This means that the oil mixture is stable and binds together with other inggridients.The oil contained in chocolate comes from cocoa fat (also fat from cocoa powder), super olein, VRPO or RPO, and milk fat from powdered milk.The mixture of types of fat or oil mixed well is thought to be caused by the relatively similar composition of fatty acids contained in each oil consisting of palmitic acid, oleic acid, and stearic acid.Aydemir (2019) reported that the manufacture of hazelnut cream using solid fats such as cocoa butter, hydrogenated palm oil, and vegetable margarine without water did not show oil separation during 30 days of storage at 24 ± 0.5°C, but with milk fat without water and coconut oil separation occurs [19].In addition, El-Hadad et al. (2011) reported the use of 20% red palm olein and 80% butterfat produced chocolate spread that has good stability of physical properties, fatty acid composition, fat stability, and natural antioxidants during 6 months of storage [13].
Table 3 shows that the melting point of the fat is 29.5-31.2°C.The greater the amount of RPO or VRPO, the higher the melting point of the fat.This is thought to be caused by RPO or VRPO having a high melting point compared to cocoa butter (32-35 °C) [8] or milk fat (28-36 °C) [20].As a comparison, palm oil has a melting point of 33.2-38.2°C [10].Kumar et al. (2016) also reported that the addition of red palm olein also increased the hardness of chocolate spread compared to chocolate spread made from 100% butterfat [14].It caused by the changing fatty acids composition where the addition of red palm olein to butter fat affects short-chain, medium-chain, and long-chain fatty acids (palmitic acid, stearic acid, and oleic acid) [14].
The addition of RPO or VRPO caused the levels of carotene in fat in a chocolate spread to increase from 5.25 ppm (control) to 11.43-78.63ppm.The greater the amount of RPO or VRPO, the higher the carotene content (Table 3).Formulas using VRPO tend to provide higher levels of carotene than RPO because VRPO contains high levels of carotene.This is because VRPO is unrefined oil extracted directly from palm fruit which is processed by simple boiling.Meanwhile, RPO is produced from a chemical refinement process from CPO.The chemical refinement process uses heating and washing so it is suspected that during the process there is a decrease in carotene levels, where carotene compounds are easily degraded by heat.
Carotene enrichment in chocolate has also been reported by Negara et al. (2014) who used 5% Spirulina platensis [21].The resulting product contains 70.33 μg β-carotene/gram.This value is close to the addition of 6% VRPO in the chocolate spread mixture which contains a carotene level of 78.63 ppm.El-Hadad et al. (2011) reported that chocolate spread using addition 20% red palm olein into butterfat increased tocopherols and tocotrienols (from 71 ppm to 282 ppm) and carotene (from 10 ppm to 148 ppm) [13].Kumar et al. (2016) reported that red palm olein enriched carotene (115.3 ppm), phytosterols (50.6 ppm), tocopherols and tocotrienols (162 ppm), and squalene (101 ppm) in chocolate spread.

Sensory Profile of Chocolate Spread
Chocolate and its derivatives are primarily consumed for their sensory properties rather than nutritional characteristic [22].Sensory properties are affected by dough ingredients, production processes, and storage conditions [23,24].Thus, sensory characteristics must be considered in product development, process, and optimization studies [22].The taste and texture of chocolate comes from cocoa powder, sugar, and cocoa butter mixtures [25].Sensory ratings for each type of chocolate are different.The main difference is in the aroma and taste profile [23].In this study, the chocolate spread was assessed based on sensory attributes including taste, color, texture, aroma, and appearance (gloss and surface smoothness).

Figure 1. Preferences of chocolate spread with addition RPO or VRPO
The panelist's assessment showed that the highest score was for taste in the control formula (4.6), color in formula 4 (4.37),texture in formula 4 (4.10), the aroma in the control formula (4.27), and appearance in formula 2 (4.17).Regarding all sensory attributes, formula 4 is the most preferred formula and is close to the control formula.The preference for formula 4 is thought to be since only 2% of the VRPO is used so that it does not cause the dominant aroma, color, and taste of the typical VRPO.
The use of VRPO is preferable to RPO which is thought to be caused by VRPO being produced with minimum heating so that it has a distinctive, soft palmy aroma, while RPO from CPO produced from palm oil mills is then neutralized and deodorized at moderate temperatures.Generally, RPO produced from the chemical refinement of CPO still has a strong palmy odor.El-Hadad et al. (2011) reported chocolate spread using 20% red palm olein and 80% butterfat had an acceptable sensory value and was close to chocolate spread made from 100% butterfat [13].Kumar et al. (2016) also reported that a mixture of 20% red palm olein and 80% butterfat has acceptable sensory attributes [14].

Table 1 .
Chocolate spread formulation (1 kg) with the addition of RPO or VRPO

Table 2 .
Particle size and oil stability of chocolate spread

Table 3 .
Melting point and carotene content of chocolate spread fat