Non-Dairy Milk Alternatives

Non-Dairy Milk Alternatives

 

Ambashree Dubey1, N.K. Nayak2, Pranav Chauhan3, Divyani Patel4 and Sunita Dawar5  

 

           Department of Livestock Products Technology, College of Veterinary Science & A.H.,

Mhow, Indore (453446), M.P., India

 

 

Introduction

 

Over the past decade, major research emphasis in all sections of food product development is to address the changing needs and to meet the present demands of consumer by creating newer alternative of health foods. Increasing urbanization has accelerated these demands; concerted research effort in functional and speciality beverage for newer products is the recent trend. In today’s world, beverages are no longer considered simply as thirst-quenchers but consumers look for specific functionality in these drinks, which forms a part of their lifestyle. Functionality in these beverages may be to address different needs and lifestyles—to boost energy, fight ageing, fatigue, stress and target specific diseases. Further, the sector is still expanding. In recent years, these changes and developments have led to newer products in the beverages sector. One such major functional requirement is milk alternatives to answer problems of cow milk allergy, lactose intolerance, calorie concern and prevalence of hypercholesterolemia (Aydar et al., 2020). In addition to the role of a plant-based diet on a decrease in cardiovascular diseases, diet rich in plant-based foods including soybeans and nuts reduces the risk of neurodegenerative disorders such as Alzheimer’s disease (Pistollato et al., 2018). As a result, the consumption of plant based milk has been increased due to absence of cholesterol and lactose, making it suitable for a group of population suffering from lactose intolerance and heart disease and in general for all.

Types of Plant based / Non-dairy milk alternatives

1. Oat milk

Oat milk is the recent emergent in the market owing to its potential therapeutic benefits. Oats have received extensive interest due to the presence of dietary fibres, phytochemicals and high nutritive value. They possess various health benefits such as hypocholesterolaemic and anticancerous properties. Health benefits of oats are associated with dietary fibres such as β-glucan, functional protein, lipid and starch components and phytochemicals present in the oat grain and that is why it is one of the promising raw materials for preparation of functional plant-based milk. They are good source of quality protein with good amino acid balance. Oat fibres are also known for their hypocholesterolemic effect by reducing total and LDL cholesterol (Truswell, 2002). They are also a good source of antioxidants and polyphenols. Oat contains 60 % starch, 11–15 % total protein, 5–9 % lipids, 2.3–8.5 % dietary fibre and 0.54 % calcium (Rasane et al., 2015). In order to diversify the oat consumption, attempts have been made to develop oat based beverages or oat milk (Deswal et al., 2014).Starch constitutes the major portion of the oats (55–60 %) with a gelatinization temperature range of 44.7–73.7 °C (Tester and Karkalas, 1996). But, this high concentration of starch creates a problem in preparation of a stable emulsion during the heat processing of oat beverage. On application of heat, starch begins to gelatinize and liquid milk tends to attain a gel like consistency with high viscosity leading to its lower acceptability. So, in order to maintain the fluidity or beverage like consistency, hydrolysis of starch is only one of the methods allowing its removal, to prevent gelatinization during thermal treatment. To resolve this problem, enzymatic hydrolysis has been investigated by researchers, to obtain an acceptable product. Despite of its health benefits, oat milk lacks calcium which is an essential nutrient for the growth and development; therefore, it needs to be fortified before its consumption as a milk alternative.

2. Soy milk

The use of soy milk was first reported about 2000 years ago in China. Soy milk was the first plant-based milk which serves the purpose of providing nutrients to the population where the milk supply was inadequate. It was also popular amongst the populations who are allergic to milk proteins and are lactose intolerant. Soy milk is a good source of essential monounsaturated and polyunsaturated fatty acids which are considered good for cardiovascular health. It serves as an inexpensive, refreshing and nutritional beverage to the consumers. Isoflavones appeared to be the functionally active component responsible for the beneficial effects of soybean. Isoflavones are well known for their protective effect against cancer, cardiovascular disease, and osteoporosis (Omoni and Aluko, 2005). Soy foods are also found to be rich in phytochemicals such as phytosterols, which are recognized for their cholesterol lowering properties (Fukui et al., 2002).Traditional process of soy milk preparation leaves a product with limited shelf life and a characteristic beany flavor. Modern soy milk production utilizes advanced technologies and equipments to maximize nutritional value, shelf-life and convenience with reduced beany flavor. Some of the widely accepted methods in order to remove or deodorize the beany flavor of soy milk are: vacuum treatment at high temperature which results in stripping off of most volatile compounds (short chain fatty acids, sterols, sulphur compounds etc.), leading to a better acceptable product to the consumers, llinois pre-blanching method where soaked soybeans were blanched in boiling water to inactivate lipoxygenase. The only disadvantage of soy milk consumption is prevalence of soy allergies, making it unsuitable for population who are allergic to soy proteins.

3. Peanut milk

Oilseeds are thought to have a high potential as an alternative source of non-dairy beverages. Among oilseeds, peanut is a promising raw material for preparation of plant-based milk but similar to soy milk, presence of beany flavor limits its applications. Peanut milk has been extensively utilized in developing countries by low income group, undernourished children, vegetarians and people allergic to cow’s milk (Diarra et al., 2005). Peanuts contain 21.5 % carbohydrates, 49.6 % fats, 23.68 % proteins and 8 % crude fibre (Settaluri et al., 2012). The functional properties of peanuts are mainly associated with presence of phenolic compounds which are known for their antioxidant function and a protective role against oxidative damage diseases like coronary heart disease, stroke, and various cancers. In several investigations, different methods were adopted by researchers to obtain peanut milk .Wet grinding, to obtain peanut extract was the most widely used method and other method using full fat or partially defatted peanut flour have been successfully reported.

4. Almond milk

The consumption of dried fruits and nuts has become an essential part of healthy living owing to their potential health benefits. Almonds contribute to the largest share in total nuts consumption. Almond contains approximately 25 % of protein, majority of which is present in the form of AMP or amandin (Sathe et al., 2002). Almond is a nutrient dense product and is an excellent source of vitamin E in the form of alpha-tocopherol and manganese. Compared to other plant-based milks, almond milk is naturally a good source of vitamins, especially vitamin E which cannot be synthesized by the body and need to be supplied through diet or supplements. Alpha-tocopherol is the functionally active component of the Vitamin E and is a powerful antioxidant which plays a critical role in protecting against free-radical reactions (Burton and Ingold,1989; Niki et al., 1989). Almonds are rich source of other nutrients such as calcium, magnesium, selenium, potassium, zinc, phosphorus and copper. Almond consumption is known to be associated with various pharmacological properties such as lipid lowering, antioxidant, laxative and immunostimulant. Being a rich source of calcium and fat and low in calorie count, it is nutritionally better than other plant-based milks. Prevalence of tree nut allergy and high cost limits its use as a beverage.

5. Coconut milk

Coconut milk plays an important part in the south East Asian cuisine. It is not only consumed as a beverage but used as an ingredient in number of sweet and savory recipes. Coconut is a nutrient dense product and is a good source of fiber. Coconut milk is rich in vitamin and minerals such as iron, calcium, potassium, magnesium and zinc. It also contains a significant amount of vitamin C and E (Seow and Gwee,1997). The use of coconut milk is associated with health benefits such as anti-carcinogenic, anti-microbial, anti-bacterial, and anti-viral. It contains a saturated fat, lauric acid which is present in mother’s milk and has been related to promote brain development. Lauric acid is also helpful in boosting immune system and maintaining the elasticity of the blood vessels. Coconut milk is rich in antioxidants such as vitamin E which helps fighting against ageing. Coconut milk consumption is rarely associated with allergenic reactions. Other benefits of coconut milk includes: helps in digestion, nourishes skin and has cooling properties. Inspite of all health benefits, presence of saturated fats limits its consumption.

6. Sesame milk

Sesame is one of the important oilseed crops in the world. It is consumed in variety of preparations like tahini, sweet meats etc. It is a source of high quality protein with a unique balance of amino acids. Sesame seed contains significant amount of lignans such as sesamin, sesamolin, sesaminol and others which are known for their functional properties. Sesame lignans are recognized to have properties such as antioxidative, hypocholesterolemic, anticarcinogenic, antitumor, and antivirus activities (Namiki, 2007). It contains significant amount of anti-nutritional factors such as oxalates and phytates (Kapadia et al., 2002). But, the oxalates are confined to outer hull and most of them are removed during decortication. Also, the compounds associated with bitterness of sesame seeds are confined to hulls therefore; decortication also helps in improvement of flavor. Various processing methods like soaking, roasting, defatting, germination, fermentation, microwave heating have been investigated for their potential in modifying functional properties of sesame proteins. Roasting and alkali soaking have been observed to improve the overall acceptability and flavor by reducing bitterness and chalkiness in sesame milk. The consumption of sesame milk can overcome the limitations associated with soy milk consumption such as presence of flatulence causing factors, prevalence of allergies towards soy proteins and beany or off flavor (Zahra et al., 2014).

Technological interventions in improving the quality and acceptability of plant based milk alternative

Improving product stability

Stability of plant-based milk depends on the size of dispersed phase particles. Plant-based milk are colloidal systems formed by large sized dispersed particles such as fat globules, solid particles from raw materials, proteins and starch granules which make it difficult to obtain a stable product to be stored, not for very long time due to sedimentation or settling of solid particles. The instability of plant-based beverages due to presence of large size particles results in a sandy, gritty or chalky mouth feel and lack of creaminess due to their low fat content (Civille and Szczesniak,1973). The stability of plant-based milk can be improved by reducing the size of dispersed phase particles using various techniques. Ultra high pressure homogenization (UHPH) is one of the promising processing technologies which results in smaller and more uniform sized particles, can be effectively utilized to improve the stability of plant-based milk (Valencia-Flores et al., 2013). Apart from achieving size reduction of colloidal particles, a simultaneous destruction of micro-organisms can be achieved by UHPH treatment due to stated effects of high-pressure on micro-organisms (Cruz et al., 2007). This technology is suitable for liquid food products, allowing a better stability of the product and at the same time giving preserving effect to the final product.

Removal of off-flavor

Soy products are gaining popularity as economical source of quality protein and their positive effects on health but presence of beany or unpleasant flavor needs to be eliminated or reduced in order to increase the acceptability of products in terms of taste and flavor (Friedman and Brandon, 2001). The two main reasons responsible for off flavor are: presence of unsaturated fatty acids and the presence of lipoxygenases (Maestri et al., 2000). Substantial efforts have been made by several researchers in exploring technologies and processes to eliminate beany flavor but, this area still needs a consideration with further exploration by the use of newer and advanced technologies. Commonly practiced approaches to solve this problem are inactivation of enzymes, removal of off-flavours by deodourization and masking of off-flavour by addition of artificial or natural flavourings. Lipoxygenase inactivation by heat is the most common technology to improve the flavor of soy milk that has been utilized for decades. Modification of traditional processing method by introducing steps like roasting, blanching and soaking in alkaline conditions have been known to reduce beany flavor in legume based milk and hence, improved the acceptability of the product.

Inactivation/removal of inhibitors

Apart from removal of off flavors, destruction of trypsin inhibitors is an important area of concern which is thought to be a cause of pancreatic hypertrophy. They are known to reduce protein absorption and hence adversely affect the human nutrition. Trypsin inhibitors are subject to denaturation and inactivation by heat but overheating to completely inactivate trypsin inhibitors may cause amino acid degradation, decrease in nutritional value and other deteriorative changes. Therefore, careful selection of time–temperature combination in thermal processing is required for processing of soy milk to obtain a product with high nutritional value. Trypsin inhibitor activity in soy milk processed by traditional, steam injection, blanching, and UHT treatment was estimated. Traditional and steam injection to 100 °C for 20 min resulted in a residual trypsin inhibitor activity of 13 % whereas, blanching inactivated 25–50 % of TIAs of the raw soy  milk. UHT treatment with increase in temperature and time has been found to result in a product with low residual trypsin inhibitor activity of app. 10 %. Other inhibitors present in soybean are phytic acid and saponins. Phytates are stable to heat and are not degraded during cooking (Davies and Reid, 1979) are known to cause poor mineral bioavailability. Effective reduction of phytates can be achieved by the action of enzyme phytase. Murugkar, (2014) studied sprouting as a non-chemical, non-thermal tool to improve the quality of soy products (soy milk and tofu). Sprouting of soybean increases protein content and also reduces fat, trypsin inhibitor and phytic acid whose reduction otherwise requires intense heat treatment or methods like ultrafiltration.

Shelf life improvement

Plant-based milk being rich source of nutrients serves an ideal medium for growth of micro-organisms, and therefore, its quality is adversely affected by the rapid growth of micro-organisms. Thermal treatment has long been used as a processing method to extend the shelf life of food products by eliminating or reducing spoilage and pathogenic micro-organisms. Heat treatment has been utilized to increase the shelf life of plant-based milk along with the objectives of increasing total solids yield and improvement of flavor whereas, excessive heating found to cause detrimental effects on nutrients (vitamins and amino acids), browning and development of cooked flavor (Kwok and Niranjan,1995). So, in order to eliminate or reduce the destructive effects on plant-based milk, various combinations of time–temperature have been employed to have best quality product. UHT processing involves direct heating methods which include steam injection and steam infusion or indirect heating in plate or tubular heat exchangers. After any of the above mentioned treatment, packaging under aseptic condition is required to maintain the sterility. Product needs to be stored under refrigeration conditions after pasteurization whereas, after in-container sterilization or UHT treatment product can be stored at room temperature for a few weeks. High-pressure throttling, ultra high pressure homogenization (UHPH), high pressure processing technologies have been investigated for their use in shelf-life extension of soy milk.

Positive Effects

• Antioxidant activity- Nut and seed milk are rich in antioxidants which reduce the risk of cardiovascular diseases, cancer, atherosclerosis and diabetes by preventing free radicals from oxidizing nucleic acids, proteins, lipids and DNA.
• Presence of essential fatty acids- Essential fatty acids such as oleic acid, linoleic acid and linolenic acid have positive effects on Alzheimer’s disease and neuroprotective effects such as supporting the axonal and dendritic growth of neurons.
• Presence of essential amino acids- Nuts and seeds have well balanced ratio of lysine to arginine which is 0:19 for hazelnuts, 0:20 for walnuts and 0:24 for almonds, which enable them to prevent hypercholesterolemia and atherosclerosis.
• They do not contain cholesterol.
• It can be an excellent option for the lactose intolerant people.
• It is rich in phytoestrogens- Soymilk includes phytoestrogens such as Genistein, Daidzein and Glycitein which are similar to estrogen molecules in terms of their structure. Genistein is a chemotherapeutic agent for various types of cancer and its consumption during intake of some common anticancer drugs like Adriamycin and Tamoxifen gives rise to a synergistic effect.
• Production process is environmental friendly- Direct greenhouse gas emission is lower for plant based milk compared to cow’s milk. Also, plant based milk waste includes high amount of bioactive compounds, antioxidants, essential oil, etc. This recycling of plant based waste products helps to decrease the environmental problem.

Negative Effects

• Low bioavailability of vitamins and minerals- Bioavailability is the ratio of a compound in an active form at the targeted site of action. Although nuts and seeds are rich in terms of minerals and vitamins, antinutrients like phytate and oxalate cause a decrease in bioavailability.
• Oral health problems- Added sugar used to sweeten plant based milk has a detrimental impact on oral health. It is one of the etiological causes of tooth decay.
• Lack of Iron- Plant based milk contains iron, but it is of a low heme variety which does not get absorbed into the body properly. Lack of heme iron in the body can cause fatigue and anaemia.
• Plant based milk usually lacks calcium and immunoglobulins that is present in traditional milk.

Producers of Vegan milk around the world

• Danone SA
• The Hain Celestial Group
• Sahmyook Foods
• Sanitarium Health and Wellbeing
• Axiom Foods
• Daiya Foods
• Vbites Food
• Earth’s own Food Company

Producers of Vegan milk in India

• Urban platter
• GoodMylk
• Karma Milk Pvt. Ltd.
• So Good
• Borges
• Sofit

 Conclusion

Many consumers are interested in reducing the number of animal products in their diet for health, ethical, and environmental reasons. The plant-based milk substitutes are a fledgling category in the plant-based food industry and its popularity has been expanded due to various factors including rising levels of lactose intolerance, different diet types, desire for a healthy lifestyle, concern for animal welfare, and environmental concerns. Though plant-based milk is rich in terms of antioxidant activity which is beneficial for the immune system and fatty acid that has a positive effect on the prevention of cardiovascular diseases, an insufficient protein amount, a low bioavailability of mineral and vitamin content, and the added sugar present a dilemma for the consumption of plant-based milk substitutes when compared to cow’s milk. Insufficient protein content can be eliminated by mixing different types of plant based milk substitutes, and, in this way, a pleasant taste can also be achieved without the need for added sugar. The lower bioavailability of calcium and various vitamins can be overcome by fermentation of plant-based milk substitutes via the use of lactic acid bacteria and yeast. Increased consumer acceptance and great potential for reducing the effect on climate during manufacturing ensures that the plant-based milk substitute market will expand.

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Non-Dairy Milk Alternatives in India as Best Substitute for cow’s Milk:A Review