1. Introduction
Cubing machines in food processing are not a new phenomenon and have progressed over the years with various promising patents. The earliest patent seems to be the apparatus used for cubing sliced material by Leibing [
1], in which the cutting works were characterised by the nature of the cut, or through the rotating knives, to obtain the cubes. Three decades after, there was a cheese cubing apparatus that used an actuated pressure plate mechanism, and an adapted screw continuously rotated in one direction with automatically released parts, which permitted a quick pressure plate retraction [
2]. A decade later, there was a meat cubing apparatus patent by Soodalter [
3], which involved, first, cutting to secure a slab from a piece of meat; second, cutting to sever a slab into elongated strips; and third, cutting to cut strips transversely into cubes. Besides the above-mentioned patents, Sokhansanj and Turhollow [
4] described cubes as larger than pellets, in the form of a square cross section of chopped biomass, and less dense depending on a variety of factors, for example, cube size. By reviewing the typical cubing operation, Sokhansanj and Turhollow [
4] demonstrated the schematic biomass flow that showed the position of the cuber and equipment layout for the biomass cubing. The commercial cube-making apparatus today, which probably emerged from the above-mentioned patents, are too expensive for small-scale food processors, especially in developing countries, to afford. Hence, there is a call to make an affordable cubing apparatus using locally available materials to help advance and develop agrofood products.
Condiments are preparation products supplemented in foods aimed at achieving specific desired changes in flavour or texture in the prepared food menu. African condiments, usually introduced during cooking in fairly small amounts, are largely of pungent flavour [
5]. Besides, many African traditional menus constitute a combination of grain cereals, green leafy vegetables, fruits, legumes, and/or starchy tubers [
6]. Legumes and their respective seeds, particularly when fermented, serve as strong condiments and are notable sources of minerals. Legume seeds equally account for about 80% of dietary protein and are the primary sources of protein for some groups [
7]. Comparing the tropics and other parts of the globe, the utilisation of legume seed is underscored by its physical form and the processes employed especially in preparing various food menus, and is highly dependent on such factors as ethnic background, customs, and traditions [
8]. Specifically and widely available in Africa,
Prosopis africana (Guill and Perr) Taub., with common names like djembe, iron tree, Malinke, and African mesquite, is a flowering plant with legume seeds, which, after the fermentation process, make the well-known condiment called “okpeye” (also called either “okpehe,” “okpiye,” “daddawa,” or “kpaye”) [
9,
10,
11,
12,
13]. In Nigeria, fermented leguminous seed condiments, largely utilised when preparing dishes, remain very key in enhancing flavours [
14,
15]. Besides the characteristic aroma (and flavour) that enhances the taste of traditional dishes and soups, the “okpeye” condiment is a rich source of protein with useful minerals and phytochemicals beneficial to human health [
9,
10,
11,
12,
13]. Despite the popularity of the “okpeye” condiment as a flavouring agent particularly among many rural and urban people [
12,
13,
16], there still remains some stigma associated with it, that is, being perceived as a low-cost (meat) substitute for poor (traditional) families [
9,
17].
The bouillon cube, also called broth or stock cube, is believed to have been introduced between the French and Germans. It is a dehydrated product and typically prepared from dehydrated vegetables, meat stock, a small portion of fat, monosodium glutamate (MSG), salt, and seasonings. It was in 1908 when “Maggi” commercialised bouillon cubes, followed by ‘Knorr’ in 1912 [
18]. In many parts of Africa (including Nigeria), bouillon cube products like Star
®, Knorr
®, and Chicken
® types are well known to occupy a very strong market base. On the other hand, there is the fermented mesquite seed (“okpeye”) food condiment, which is craft based and traditionally produced by well-trained artisans who largely learned this trade from their friends and relatives over time. Indeed, the commercial success of fermented mesquite seed (“okpeye”) food would strongly depend on the observance of good hygiene/manufacturing practices (GHPs/GMPs). Information regarding quality standards, especially in the production process of fermented mesquite seed “okpeye,” remains insufficient. Additionally, there continue to be (quality) inconsistencies in emergent output/product [
19].
There appears to be a notion in the Nigerian populace that industrially commercially available bouillon cubes, like Star
®, Knorr
®, and Chicken
® types, contain more nutrients than other traditionally handcrafted condiments, like the “okpeye.” Additionally, the traditional (“okpeye”) condiment is yet to attain such widespread status like those commercial bouillon cube types (e.g., Maggi cube). Characteristic putrid odour, objectionable packaging materials, short shelf life, and stickiness are among the reasons mitigating the widespread status of “okpeye” condiment [
20]. To improve this condiment product is, therefore, warranted to enable it compete favourably with commercially available bouillon cubes. However, there is paucity of relevant information about comparisons between the local “okpeye” condiment and commercial bouillon cube products. Specifically, quality comparisons between the “okpeye” condiment pressed in cube form and commercially available bouillon cube products have not yet been published. To supplement existing information, this work focused on determining the cubing fabrication/costing and machine performance of African fermented “okpeye” condiment quality attributes, compared with commercial bouillon types. The procedure for making the “okpeye” condiment is likened to those of artisans. The bouillon cube products include the commercially available Star
®, Knorr
®, and Chicken
® types. Subsequent sections include the materials and methods, where all the processes used to implement the experimental program are explained. This is followed by the results and discussion, limitations and direction of future work, and conclusions.
4. Limitations and Direction of Future Work
Given that the cubing machine was fabricated using the conventional workshop procedure, the degree of accuracy and precision might likely be questioned, which could be considered a limitation. The idea here is to make a cubing machine, and to press “okpeye” into cube forms, then, to make some comparisons with commercial bouillon types. Another potential limitation could be the costing, which has two facets. One facet is the overall price fluctuations in Nigeria. The other facet is the price variations specific to the materials used. If this cubing machine were to be fabricated today, a higher bill might be realised. Another limitation could be the machine performance, largely dependent on the power output of operator, which decrease with increase in the operation time.
A direction of future work should be to increase the accuracy and precision of fabricating the cubing machine, which could help enhance the (cubing) process as well as (“okpeye”) product development. It would be useful if a business model is developed to elaborate on how a transition from artisanal to industrial production can take place. Additionally, it would be useful to have artisans assess the cubed “okpeye”, as this would help understand their opinion about the cubing machine. This could be carried out alongside the shelf assessment of the cube “okpeye” condiment, specifically evaluating different storage conditions/contexts, and adding to the parameters of the current study, to determine both colour and textural aspects, which would involve making comparisons with commercially available bouillon cubes, to help supplement existing information.
5. Conclusions
The cubing fabrication, costing, and machine performance on African fermented “okpeye” condiment quality attributes, compared with commercial bouillon types, were performed. The “okpeye” cube condiment measures 0.0024 m2 approximately, while the cost of fabrication is considerably low (₦45,740.00) and can be afforded by local producers. The performance of this machine is largely dependent on the power output of the operator and decreases with the increase in time of operation.
The fermented condiment was significantly (p < 0.05) higher in protein, fat, and moisture as well as calcium, iron, magnesium, and manganese compared with the bouillon cubes. All the samples were fair sources of vitamins B1, B2, B3, and E, but the condiment was higher in vitamin E content. The very low Na content in “okpeye” can help to balance the Na/K ratio for heart pressure maintenance compared with the bouillon cubes. The microbial loads resembled (p > 0.05) across the tested samples.
Indeed, the regular use of this fermented “okpeye” condiment in food/soup preparations should be promoted, given its capacity to sustain consumer health and well-being. Importantly, we demonstrated in this current study that the “okpeye” condiment can be cubed, competes favourably in terms of quality attributes, and is a very promising substitute to commercially available bouillon cubes in food preparations.