Trang 1 TECHNOLOGY AND EDUCATIONMINISTRY OF EDUCATION AND TRAININGHO CHI MINH CITY UNIVERSITY OF LECTURER: HOANG VAN CHUYEN, PHDSTUDENTS: DO LE ANH DUY NGUYEN THANH NGAN S K L 0 0 9 6 7
INTRODUCTION
Rationale
Macadamia oil cake (MOC), a byproduct of macadamia oil extraction through cold pressing, is rich in nutritional value and protein content, ranging from 15% to 50% This makes it a valuable feedstuff for cattle Additionally, MOC is known for its appealing flavors, making it a suggested ingredient to enhance the sensory quality of various food products.
Macadamia oil cake (MOC) is a promising alternative protein source, containing 24.5% crude protein and 24.9% crude fiber, making it suitable for poultry and ruminant diets (Skenjana, 2012; Acheampong-Boateng et al., 2008) Research indicates that incorporating MOC into animal feed enhances growth performance and carcass characteristics in lambs (Acheampong-Boateng et al., 2017) Furthermore, studies have demonstrated its effectiveness in replacing traditional feed ingredients such as corn, soymeal, and wheat, highlighting its high fiber content, essential nutrients, and beneficial effects on gut health (Yadav & Jha, 2021) While primarily studied for animal nutrition, MOC also holds potential for human food applications, particularly in bakery products like cookies and bread This research aims to develop MOC-fortified cookies and bread, enhancing their nutritional and sensory qualities.
Research hypothesis
Nutritional composition in macadamia oil cake can contribute to nutritional value of bread and cookies
Protein content and fat content from MOC fortifications will affect the structural properties of bread and cookies
The addition of macadamia oil cake may help improve sensory quality of bread and cookies
Research objectives
Determine chemical composition of macadamia oil cake
Evaluate the effect of MOC addition on color, texture, physical properties, sensory properties and nutritional composition of bread and cookies
Determine the most suitable ratio of macadamia oil cake in bread and cookies.
Research object and research scope
- Macadamia oil cake obtained from hydraulic pressing
- Macadamia oil cake fortified cookies and bread
- Investigating nutritional and sensory qualities of bread and cookies on different levels of macadamia oil cake addition.
Research significance
Evaluate the effect of MOC addition on physical properties of cookies and bread
Evaluate the effect of MOC addition on nutritional and sensory quality of cookies and bread
Result from this result would be useful to develop MOC products manufacturing
Practical application in producing MOC bakery products
Increasing nutritional quality of cookies and bread
Improve sensory quality of cookies and bread
OVERVIEW
Overview of macadamia oil cake
2.1.1 Origin and distribution of academia trees
The macadamia nut is known as the Australia’s only commercial food crop indigenous and the world’s finest nuts due to its unique, delicate flavor, crunchy texture
Macadamia is in the Proteaceae family and found to include 5 species in Australia, and
10 species in other parts of the world Only 2 of 4 southern Macadamia species are edible, the smooth-shelled M integrifolia and the rough-shelled M tetraphylla However, only
M.intergrifolia has been developed commercially
M.intergrifolia is native species of the subtropical rainforest in the south-east region of
Queenland, and it is distributed between 25.5° to 28.3°S latitude Sclerophyllous leaves and dense clusters of fine, proteoid roots allow the tree to adapt the harsh environments
The world macadamia production takes place between 0° and 32° latitudes Hawaii is leading nation in macadamia cultivation with the 9000h in production (Stephenson, 2005)
2.1.2 Production situation and consumption situation of macadamia nuts
Of all tree nuts consumption, the macadamia nuts consumption is only 3% For instance, if there are 650,000 t of almonds, 370,000 t of walnuts, 330,000 t of hazelnuts,
250,000 t of cashews, 200,000 t of pistachios and 110,000 t of pecans are consumed, only 25,000 t of macadamia nuts are consumed
Figure 2 1 World macadamia consumption (t) (2003) Australia exports about 50% the world’s macadamia Expansion of plants is growing massively, particularly in Australia and South Africa (Stephenson, 2005)
Table 2 1 World macadamia production and exports
The images depict the complete Macadamia integrifolia seed, highlighting key features such as the hilum, micropyle, and outer suture Each shell exhibits a unique pattern of light brown speckles Additionally, cross-sectional photographs reveal variations in the thickness of the seed coat, with cuts made both normally and parallel to the outer suture.
The ‘‘normal’’ section (c) exhibits a nearly constant thickness, while the shell thickness of the
‘‘parallel’’ section (d) varies (Schüler et al., 2014)
2.1.4 Chemical compositions of macadamia nuts
The levels of the elements in all the Macadamia nuts are reported to be in the decreasing order of Mg > Ca > Fe > Zn > Cu > Cr > As (Moodley et al., 2007)
Table 2 2 Nutritional value of raw macadamia nuts
Macadamia nuts are rich in monounsaturated fats, comprising 59% of their composition They contain a water content of 1.4g per 100g, and their carbohydrate percentage is comparable to that of other nuts like pecans and Brazil nuts.
Macadamia nuts, with a fat content of 13.8g per 100g, have the highest fat levels among all nuts, as noted in a study by Brufau et al (2006) Despite their high fat content, they contain the lowest protein level at 7.9g per 100g Additionally, raw macadamia nuts boast the highest energy value of all nuts, providing 718 kcal per 100g.
Macadamia nuts do not contain significant amounts of vitamins A and D, as noted by the USDA Database, which also reports a vitamin E content of 0.54mg However, research by Moodley et al (2007) indicates that neither vitamins A nor E are present in detectable levels in macadamia nuts, confirming that these vitamins are not predominant in this nut variety.
Macadamia nuts are a rich source of nutrition, high in unsaturated fats, plant protein, and essential minerals The nutritional composition of these nuts can vary significantly based on factors such as cultivar, seed age, and growing conditions For instance, macadamia nuts contain the highest fat content of any nut, averaging around 75% fat and providing 733 kcal per 100 g However, studies have reported varying fat percentages, ranging from 59.2% to 78.4% In New Zealand, locally cultivated macadamia nuts show lipid content fluctuations between 69.1% and 78.4% (Munro & Garg, 2008).
Macadamia nuts contain sugar in the form of fructose, glucose, maltose, and sucrose, with sugar levels ranging from 1.36% to 4.57% Additionally, Australian macadamia nuts have a fiber content of 6.4%, while those grown in the United States boast a higher fiber level of approximately 8.6%.
Macadamia nuts should ideally have a low moisture content between 1.2% and 2.1%, as this helps minimize microbial growth and improves their shelf life and overall quality (Munro & Garg, 2008).
Macadamia nuts are a valuable source of plant protein, containing between 7.9% and 8.4% protein Notably, tryptophan is identified as the first limiting amino acid in these nuts.
Macadamia nuts are a rich source of all essential amino acids, including the seven that the body cannot produce on its own (Munro & Garg, 2008).
Macadamia nuts are rich in essential micronutrients, providing 368 mg of potassium, 130 mg of magnesium, 85 mg of calcium, and 188 mg of phosphorus per 100 grams Additionally, they contain trace amounts of iron, zinc, and copper, making them a nutritious choice for enhancing your diet.
Macadamia nuts are a rich source of essential vitamins, containing niacin (2.5 mg/100 g), thiamin (1.2 mg/100 g), riboflavin (0.2 mg/100 g), and pyridoxine (0.3 mg/100 g) They also provide pantothenic acid (0.8 mg/100 g) and vitamin C (1.2 mg/100 g) Notably, macadamia nuts have the lowest folate content among all nuts, with just 11 µg of folate per 100 g (Munro & Garg, 2008).
Nuts are high in fat, with over 75% consisting of monounsaturated fatty acids (MUFA) Macadamia nuts are particularly rich, containing 77.4% MUFA per 100 g of fat, primarily made up of 58.5% oleic acid and 18.7% palmitoleic acid They have a low polyunsaturated fatty acid (PUFA) content of only 4.4%, which includes 2.6% alpha-linolenic acid and 1.8% linoleic acid Additionally, macadamia nuts contain 18.2% saturated fatty acids, predominantly consisting of 2.95% eicosanoic acid, 8.9% palmitic acid, and 4.3% stearic acid.
Four tocopherols and four tocotrienols, both of which exist in α-, β-, γ-, and δ-forms, make up the eight distinct forms of vitamin E, a significant lipid-soluble phenolic antioxidant (Munro & Garg, 2008)
Macadamia nut oil contains 1618.3 àg of phytosterols overall, including 73.3 àg of campesterol,
Macadamia nut oil is rich in phytosterols, containing 38 µg of stigmasterol and 1506.7 µg of β-sitosterol per gram Additionally, it has 185 µg of squalene per gram, which is utilized by plant cells to synthesize phytosterols Furthermore, macadamia nuts themselves provide 8–10 mg of campesterol and 108–144 mg of β-sitosterol per 100 grams.
8 edible nut, for a total phytosterol content of 116–187 mg/100 g of edible nut No stigmasterol is present (Munro & Garg, 2008)
2.1.5 Health benefits of macadamia nuts
The composition of both raw, dried and roasted macadamias typically contain:
Mineral matter: 1.6% including Potassium, Phosphorus, Magnesium, Calcium,
Selenium, Zinc, Copper and Iron
Vitamins: Vitamin B1, B2, B5, B6, E, plus niacin and folate
Phytochemicals: Antioxidants including polyphenols, amino acids, selenium and flavonols plus plant sterols
Energy value: 3000 kilojoules per 100 g (727 calories)
Macadamia nuts are free from trans fatty acids and cholesterol, making them a healthy choice They contain a higher percentage of monounsaturated fats compared to other natural products Similar to olive oil, macadamia oil shares a comparable composition and application Additionally, macadamias are low in oxidizing polyunsaturated fats and harmful saturated fats, contributing to their health benefits (Stephenson, 2005).
Macadamia nuts offer significant health benefits by enhancing metabolism, aiding in weight management, and reducing the risk of conditions like insulin resistance and dyslipidemia Rich in monounsaturated fats, such as 18:1ω9 and 16:1, they support healthy lipid levels in the bloodstream Although high in fats and calories, macadamia nuts do not negatively impact body weight, making them a nutritious addition to a balanced diet.
45 to 90g of nuts does not affect health adversely
Overview of bread
Bread, a staple food for nearly half of the global population, is created by kneading flour with water, salt, and yeast, then fermenting and baking it The variety of bread types and recipes reflects the diverse eating habits across different regions The production process and quality of bread are primarily influenced by the use of wheat flour and yeast (Lê, 2019).
Bread is a staple food in regions such as the Middle East, Central Asia, North Africa, Europe, and cultures influenced by Europeans in the Americas, Australia, and Southern Africa, while rice and noodles dominate in parts of South and East Asia Typically made from wheat-flour dough that is leavened with yeast, bread's airy texture is due to the fermentation process Common wheat, known for its high gluten content, is the primary grain used in bread-making, although other wheat varieties like spelt, emmer, einkorn, and kamut are also utilized Non-wheat cereals such as rye, barley, oats, and rice can produce bread, often blended with wheat flour to enhance gluten levels For gluten-free bread, alternative flours from almonds, sorghum, corn, and legumes are used, although they may require additives like xanthan gum or eggs to improve texture and structure Renowned types of bread include French and Italian varieties.
British bread, European bread, American bread, Eastern bread, festive bread, etc (Treuille & Ferrigno, 2008)
Table 2 3 Sweet bread nutrition facts in 100g bread
In a 2010 study by the European Commission, the EU's bread market was estimated at approximately 32 million tons, with industrial and artisan bakers sharing a roughly equal market share, though significant regional differences exist The industrial sector leads production in several countries: 80% in the UK, 40% in Germany, 35% in France, 81% in the Netherlands, and 19% in Spain On average, EU member states consume about 50 kilograms of bread per person annually, predominantly white bread, with the UK, Spain, and Ireland consuming less than this average, while Germany and Austria lead with around 80 kilograms each Turkey tops global bread consumption at 200 kilograms per person, followed by Serbia and Montenegro at 135 kilograms and Bulgaria at 133 kilograms Whole grain bread holds a modest 3% market share in the UK and Southern Europe, but reaches 10% in Germany, with Nordic countries showing a higher preference for whole grain despite overall consumption remaining below recommended levels In the Netherlands, white bread is favored in both luxury and small bread markets, followed by multigrain options.
11 whole grain), and white bread having roughly 25% of the market share each (Folloni & Ranieri,
According to NPD's National Eating Trends survey (Bureau, 2012), 68% of consumers ate bread in the last two weeks, significantly outpacing the consumption of bagels, buns, or crackers This highlights bread's status as a staple food among American consumers In 2010, the average American enjoyed 77 meals featuring bread each year, whether at home or on the go, marking an increase from a previous low of 73 meals per person annually.
2009 but a minor decrease from the 80 meals reported in 2006 According to Euromonitor
(2011), total retail sales of bread in the United States (U.S.) were $21.4 million in 2010, growing at a 1.6% compound annual growth rate (CAGR) since 2006 (CAGR of 1.2%) Sales are anticipated to reach US$23.6 million
In South America, Argentina and Chile are the leading consumers of wheat bread, while other countries primarily rely on rice and maize as staple foods In Argentina, wheat serves as the primary source of calories and ranks as the second source of protein, following beef.
A typical Argentine consumes about 12,000 kJ of energy per day, 31% of which comes from products derived from wheat The average person consumes 96 kg of bread annually in Chile,
In Argentina, the average per capita bread consumption is 74 kg, with 70 kg attributed to industrial bread and 4 kg to craft bread Peru follows with 28 kg, Brazil with 27 kg, and Colombia with 24 kg Notably, Chile ranks just behind Germany for the highest per capita bread consumption globally.
Overview of cookies
In the US, cookies are flour-based products made from soft wheat, typically high in sugar and shortening while containing low water content In contrast, the UK refers to a similar item as a "biscuit." It's important to note that in the US, the term "biscuit" describes a type of chemically leavened bread (Hoseney, 1994).
Cookies are categorized by their dough properties, with hard doughs associated with bread and short doughs linked to cookies Unlike cake batter, short doughs have lower water content and limited gluten development, making them distinct in texture and composition (Hoseney, 1994).
Figure 2 3 A few types of cookies There are various ways to group biscuits:
By name: For example: cookies, biscuits, crackers will be distinguished based on hardness and texture
By method of dough forming and dough piece forming: wire-cut, extruded, laminated, co-extruded, etc
By the enrichment of the recipe with fat and sugar (Manley, 2011)
Table 2 4: Butter cookie nutrition facts in 30g cookies
The global cookies market, valued at USD 44.01 billion by 2025, is expected to experience a compound annual growth rate (CAGR) of 5.3% Cookies, which serve as convenient ready-to-eat meals, are available in a wide range of flavors, sizes, and price points, making them a popular choice for consumers at any time of day.
Over the years, cookie consumption has shown a steady increase, with bar cookies leading as the most popular type Following closely are drop cookies, while molded and rolled cookies also enjoy a significant share In contrast, other cookies remain the least favored among consumers.
Figure 2 5 Cookies market share by region in 2018
In 2018, North America dominated the global market Asia Pacific is expected to keep growing at the fastest rate at a CAGR of 6.8% between 2019 and 2025.
Research situations of cookies and bread fortified with nuts and oil cake
Research on fortified cookies and breads in Vietnam is limited, with a particular lack of studies on oil cake nuts In 2013, Hiền et al explored the addition of cashew nuts to cookies, successfully developing a positive product procedure That same year, they also examined cookies fortified with soymeal, focusing on the impacts of butter, eggs, and baking conditions (time and temperature) on quality Additionally, a study by Liểu in 2017 demonstrated that incorporating lotus seeds into hamburger buns not only enhances their nutritional value but also adds a distinctive flavor.
International research on oil cakes and nuts reveals promising opportunities for enhancing food products and addressing malnutrition Studies, such as those by Behera et al (2013), demonstrate that incorporating soy and peanut oil cakes into cookies can significantly boost protein content by substituting wheat flour Additionally, Jukić et al (2019) found that up to 60% of wheat flour can be replaced with pumpkin seed oil cake in biscuits without compromising quality, highlighting its potential as a healthful alternative shortening.
A study by Szydłowska-Czerniak et al (2021) found that incorporating rapeseed oil into rapeseed press cake cookies enhanced their antioxidant content However, the sensory evaluation of these cookies indicated lower taste and texture scores.
Research on enriched bread, particularly those fortified with walnut oil cake and walnut oil, has demonstrated promising outcomes, notably in terms of antioxidant levels and health benefits Nevertheless, the study also identified certain drawbacks that warrant consideration.
15 recorded, such as the increase of hardness, dark crumb, reduction in bread volume (Pycia et al.,
A study on hemp cake bread revealed a reduction in volume and adverse effects on the structural and textural properties of the bread crumb However, incorporating hemp cake into bread enhances its nutritional profile, particularly in protein content and essential macro and micro-elements, including iron.
Overall, these researches aim to improve product nutritional quality, and reduce the waste of oil industry
MATERIAL AND RESEARCH METHODS
Materials and equipment
DAMACA NGUYÊN PHƯƠNG JSC, located at No 12 Loc Xuan village, Phu Loc commune, Krong Nang district, Dak Lak province, has supplied macadamia oil cake that is ground and stored at -18℃ for experimental use.
Purpose: to reduce size of MOC powder, and to have fine, consistent powder that is easy to mix with other ingredients
Procedure: Put MOC pieces into grinder, operate the grinder, start to grind MOC until it becomes powdery form Sieve the powder through a 0.25mm sieve
Purpose: Lengthen the shelf-life of MOC powder, prevent MOC powder from absorbing moisture and infection
Procedure: the powder kept in a zip bag is put in the fridge at -18℃
The flour used during experiment is Bakers’ Choice All Purpose flour (number 11)
Table 3 1 Nutrition fact of Bakers’ Choice All Purpose flour (number 11)
Nutritional composition Serving per 100g flour
Table 3 2 Materials used and the company where they are produced
Baking sugar (powdered sugar) Đường Biên Hòa JSC
Wholemilk Powder Instant Fortified NZMP (FONTERRA)
Non-sugar fresh milk Vinamilk
Condensed milk Ngôi sao Phương Nam
Research methods
3.2.1 Preparation of cookies fortified with macadamia oil cake
Figure 3 2 MOC cookies processing flowchart
Procedure: all the ingredients are weighed by 2-decimal-point balance
Table 3 3 Design of composition of cookies
The M0 sample is the control sample M15, M20, M25 are respectively fortified cookie samples with the ratio 15%, 20%, 25% of MOC powder
Procedure: put flour on a 0,25mm sieve and start sieving
Procedure: soften the butter at room temperature Then add sugar into the butter bowl, mix well until the color turns lighter
Procedure: put all the ingredients into mixing bowl and mix well Mix until the mixture become consistent
Procedure: Let the mixture sit in 10 minutes at room temperature
Procedure: Dough was spread on a flat tray covered by parchment paper, and flattened by a rolling pin The dough thickness was 0.5cm
Procedure: use a cookie cutter to cut dough sheet into circular shape Put circular cut dough onto a tray covered by parchment paper
Procedure: Pre-heat the oven at 190℃ in 15 minutes Put the tray into oven and bake at 180℃ in 15 minutes
Procedure: put baked cookies on a cooling rack
Procedure: put cookies in air-tight zipper bag with desiccant bags inside Store in a dry, cool place, avoid sunlight
3.2.2 Preparation of bread fortified with macadamia oil cake
Figure 3 3 MOC bread processing flowchart
Procedure: put all the ingredients into mixing bowl and mix well Mix until the mixture become consistent
Table 3 4 Design of composition of bread
Procedure: let the mixture sit for 15 minutes at room temperature for a total of 4 times, 55-60 minutes in total
Procedure: Fold the outer edge of the dough in the middle about 10-12 times
To prepare the dough, divide it into six equal portions, each weighing approximately 60 grams Create a smooth surface for each dough ball by folding the edges toward the center, then roll the dough to form a pillow shape Finally, place the shaped dough into the mold, ensuring that each mold contains three pieces of dough.
Procedure: cover the mold with a towel to prevent the dough from drying out, incubate until the bread has doubled in size, about 30 minutes
Procedure: Pre-heat the oven at 160 C in 10 minutes Put the tray into oven and bake at 160 C in 30 minutes
Procedure: put baked bread on a cooling rack
Procedure: bread is placed in inner zip-top bags with desiccant packs or paper cartons with lids The bread should be kept in a cool, dry location
Moisture content in samples is determined using the air-oven method as outlined in Method 44-15.02 (AACC, 2000), where the temperature is consistently maintained at 103° (±1°) Measurements are taken in triplicate for each sample to accurately calculate the loss in weight attributed to moisture.
𝑚 1 × 100 m1: weight of sample before drying (grams) m2: weight of sample after drying (grams)
Using 3 selected cookies, using Vernier calipers to determine the thickness Average value of 3 cookies is determined (AACC, 2000)
Figure 3 4 Demonstration of diameter measuring (left) and thickness measuring (right)
Spread ratio of cookies was calculated as diameter (length) to thickness ratio by the equation (Shrestha & Noomhorm, 2002):
Each bread was weighed and then measured for volume using a rapeseed displacement volumeter (Schoenlechner et al., 2013)
Specific volume (cm 3 /g) as the ratio of the volume (cm 3 ) and the mass of the bread (g) was calculated following the AACC Approved Method 10-05.01 (AACC, 2000)
The texture analyzer (Model: Brookfield CT3) was utilized to assess cookie hardness by compressing each cookie until it broke into two large pieces The maximum force measured at the point of fracture indicates the hardness of the cookie (Gargi Ghoshal & Kaushik, 2020).
The Three-point bend (TPB) method is utilized in experiments to assess the hardness and brittleness of cookies by employing a blade to break them This method measures peak force and slope, which are indicators of the cookie's hardness and brittleness (Woody, 2003).
The texture profile analysis (TPA) was conducted using a Brookfield CT3 texture analyzer equipped with a TA-AACC3 probe, featuring a trigger load of 4.0 g and a test speed of 1 mm/s Key parameters such as hardness, elasticity, cohesiveness, and the stalling rate of the TPA curve were thoroughly analyzed.
The color of cookies and bread was analyzed using a CR-400 Konica Minolta colorimeter, which measures color in terms of L* (black to white on a 0–100 scale), a* (with +a* indicating red and –a* indicating green), and b* (with +b* indicating yellow and –b* indicating blue) (G Ghoshal et al., 2016) The deltas for L* (ΔL*), a* (Δa*), and b* (Δb*) can be either positive or negative To ensure accuracy, measurements were taken from three different areas to calculate the mean results.
∆𝐸 = √(𝐿 ∗ − 𝐿 ∗ 0 ) 2 + (𝑎 ∗ − 𝑎 0 ∗ ) 2 + (𝑏 ∗ − 𝑏 0 ∗ ) 2 Where L*, a*, b* are the color values of fortified samples;
𝐿 ∗ 0 , 𝑎 0 ∗ , 𝑏 0 ∗ are the color values of control sample
According to (Mokrzycki & Tatol, 2011), in the CIEL∗a ∗ b ∗ space, a standard observer sees the difference in color as:
• 0 < ∆E < 1 - observer does not notice the difference,
• 1 < ∆E < 2 - only experienced observer can notice the difference
• 2 < ∆E < 3.5 - unexperienced observer also notices the difference,
• 3.5 < ∆E < 5 - clear difference in color is noticed,
• 5 < ∆E - observer notices two colors are different.
A sensory test utilizing a 9-point hedonic scale will be conducted to evaluate cookie samples Twenty randomly selected judges will score the cookies based on criteria including color, shape, texture, sweetness, flavor, mouthfeel, and overall acceptability The overall acceptability will be assessed on a scale from 1 (dislike very much) to 9 (like very much) (Gargi Ghoshal & Kaushik, 2020).
Kjeldahl method comprises 4 main steps: digestion, neutralization and distillation, and titration
In digestion, use catalyst and H2SO4 at until the solution becomes clear This means all organic matter completely broke down
In neutralization and distillation step, dilute the digest with water Use Alkali-containing sodium thiosulfate to neutralize H2SO4
The digest is mixed with water, and sodium thiosulfate is introduced to neutralize sulfuric acid The resulting ammonia is then distilled into a boric acid solution, where methylene blue and methyl red serve as indicators.
Finally, using HCl to titrate the borate anion
𝑁 𝐻𝐶𝑙 = normality of HCl in moles/1000 mL
Corrected acid vol = (mL standardized acid for sample) – (mL standardized acid for blank)
Total ash content was determined according to AACC 08-01.01 standard with corrections to suit experimental conditions
To determine the ash content in a sample, a temperature range of 550-600℃ is utilized to incinerate the organic matter over a period of approximately 6-7 hours After combustion, the remaining ash is weighed, allowing for the calculation of the ash percentage in the original sample using a specific formula.
- Dry the crucible in the oven at 105ºC for 1 hour to constant weight, cool in a desiccator and weigh to determine the mass of the crucible
- Weigh 3g sample into the crucible and weigh to determine the mass of the crucible and sample before heating
To conduct sample heating, maintain a temperature of 550℃ for approximately 6-7 hours until all organic matter is converted to white ash Once the white ash is formed, carefully remove it and cool it in a desiccator Finally, measure the mass of the crucible along with the sample post-heating to obtain accurate results.
Ash content (X) is calculated according to the formula:
G1: mass of crucible and sample before heating (g)
G2: mass of crucible and sample after heating (g)
1 Weigh 2g of sample that has been previously dried in vacuum oven at 95–100°in 5 hours
2 Quantitatively transfer sample to extractor and extract with petroleum ether for 4 hours at condensation rate of 5–6 drops/sec to 16 hours at 2–3 drops/sec rate
3 Remove ether from collection flask or beaker at low temperature (below auto-ignition temperature of solvent used) volatilization before oven drying
4 Dry fat remaining in previously dried and tared fat beaker or flask in oven at 100° for 30 min Desiccate and cool
5 Weigh, and repeat step 4 to constant weight
Eurofins Sắc Ký Hải Đăng food testing laboratories, located at Lot E2b-3, Street D6, Saigon Hightech Park, Tan Phu Ward, District 9, Ho Chi Minh City, Vietnam, will conduct an analysis of essential nutritional components, including dietary fiber, mineral content, and microbiological criteria.
Statistical methods
Each experiment will replicate 3 times The results were expressed as the mean value ± standard deviation To verify the differences between samples, the result will be analyzed by using Excel
2016 and performing Analysis of Variance (ANOVA) test using Minitab 20 at a significance level of 95%
RESULT AND DISCUSSION
Chemical composition of Macadamia oil cake powder
Table 4 1 Chemical composition of MOC powder
Macadamia oil cake (MOC), a byproduct of macadamia nut oil production, retains valuable nutrients that can be repurposed for food applications Research by Acheampong-Boateng et al (2008) indicates that MOC contains 19.5% crude protein, 10.4% crude fat, 2.8% ash, and 24.9% crude fiber, with calcium and phosphorus levels at 0.24% and 0.29%, respectively While MOC is primarily investigated for animal feed (Tiwari & Jha, 2017), our study reveals a higher protein content of 21.6%, surpassing Mikasi's (2018) findings of 14.7% Additionally, our research shows a fat content of 30.4%, significantly exceeding Mikasi's 8.5%, and a crude fiber content of 6.27%, compared to Mikasi's lower figure of 0.93% Furthermore, the ash content in our study is greater than the 1.93% reported by I P Rao et al (2020).
Effect of MOC fortification on quality characteristics of cookies
4.2.1 Changes in color values of cookies
The color of the cookies surface is one of important factors beside texture and taste, to evaluate the initial consumer acceptability of the products (Zucco et al., 2011)
The surface color of cookies is developed during baking, primarily due to non-enzymatic browning processes such as Maillard reactions between reducing sugars and amino acids, as well as starch dextrinization and sugar caramelization.
The result of surface color of cookies was evaluated by CIE L* a* b* system and shown in the table 4.2
Table 4 2 Color parameters of MOC cookies
M0 (0% MOC:100% WF) 75.14±0.62 b -0.49±0.39 b 34.27±2.7 b - M15 (15% MOC:85% WF) 78.30±0.48 a 1.5±0.26 b 34.83±0.53 b 4.65±0.51 b M20 (20% MOC: 80% WF) 72.62±1.41 bc 6.28±2.96 a 39.59±0.24 a 9.28±3.53 ab M25 (25% MOC: 75% WF) 71.17±2.36 c 8.38±1.61 a 40.06±0.73 a 11.41±2.51 a Values are means ± SDs of three replicates Means of the same row followed by superscript letters are significantly different (p