From Pit to Pour: My Adventure with Apricot Seed Milk!

Hey everyone! So, you know how the world’s going nuts for plant-based milks, right? We’re all looking for something sustainable, good for us (especially if lactose is not our friend!), and packed with protein. It’s a big deal, and honestly, I’m all for it. These alternatives aren’t just for your morning cereal; they’re becoming super important as functional food ingredients, bringing along a host of goodies like essential fatty acids, vitamins, minerals, and those cool bioactive compounds.

But, let’s be real, some of the usual suspects on the shelves – think almond or soy milk – sometimes miss the mark. Maybe the protein’s a bit low, the taste isn’t quite there, or they just don’t behave well in recipes. That’s why I got super excited when I stumbled upon a new idea: using apricot seed press cake (APC for short). Yep, you heard that right – the stuff left over after cold-pressing apricot seeds for their oil. Turns out, this “waste” is a goldmine!

What’s the Big Deal with Apricot Seed Press Cake?

So, this APC stuff is a by-product of the apricot processing industry, and it’s usually just… well, leftover. But get this: it’s absolutely loaded with protein – we’re talking nearly 50% (49.75% to be exact!). Plus, it’s got essential amino acids and those good-for-you unsaturated fatty acids. Talk about a hidden gem! Using APC is a fantastic example of waste valorization, which is just a fancy way of saying we’re turning agricultural by-products into something valuable and high-quality. It’s a win for sustainability and a win for our kitchens.

Making milk from APC is a pretty fresh approach to plant-based alternatives. This Apricot Seed Milk (let’s call it ASM) boasts high protein, essential fatty acids, and zero lactose. That makes it a brilliant option for anyone who’s lactose intolerant or just rocking a plant-based diet. And if you take it a step further and spray dry the ASM, you get Apricot Seed Milk Powder (ASMP). This powder form is a game-changer for storage stability and opens up even more ways to use it in functional foods. While plant-based protein powders are all the rage, the world of apricot seed milk powder is still pretty new territory.

Diving Deeper: My Journey with ASM and ASMP

My mission, should I choose to accept it (and I did!), was to really get to know the physicochemical, sensory, and nutritional sides of ASM and ASMP. There’s a bit of a knowledge gap in the science world about these products, and I was eager to fill it. Unlike some other research out there, this dive was all about evaluating the nitty-gritty of apricot seed-derived goodies – their composition, how they function, and where they could fit into our food systems. It’s all about expanding our horizons on alternative protein sources and making food production more sustainable. By turning APC into these high-value ingredients, we’re tackling waste and meeting that ever-growing demand for plant-based, protein-rich options. It’s innovation in action, bridging sustainability, nutrition, and the development of functional foods.

For this adventure, I got my hands on apricot seeds of the Hacıhaliloğlu variety. Fun fact: this variety has a Protected Designation of Origin (PDO) in Europe since 2017! These beauties came from Malatya province in Türkiye, the apricot capital. The APC was made by cold-pressing these sulfur-free seeds to get the oil out. What was left – the oil-free seeds – became our star APC. This APC was then ground into a fine powder and mixed with distilled water. After a good whizz in an Ultra-Turrax homogenizer and filtering through cloth bags, voilà! Apricot Seed Milk (ASM) was born. I kept it chilled at 4°C, ready for its close-up.

To get the Apricot Seed Milk Powder (ASMP), I used a lab-scale spray dryer. After some preliminary tests, I dialed in the settings: air inlet temperature at 150°C, 8% maltodextrin concentration, and an aspiration speed of 25 m³/h. The resulting powder was carefully stored, also at 4°C, waiting for its turn under the microscope (figuratively speaking, mostly!).

The Nitty-Gritty: What’s Inside?

Let’s talk numbers! The APC itself had 6.67% moisture, 5.3% ash, a whopping 49.75% protein, and 6.59% fat. Now, if you look at hazelnut pulp, its composition can vary. Some studies report hazelnut pulp with around 25% protein and much higher fat (45-62%). My APC had more protein and less fat, which probably comes down to a more intense pressing process for the apricot seeds, squeezing out more of that oil. Plus, apricots and hazelnuts are just different, and pressing conditions like temperature and nozzle size play a role too.

Now for the Apricot Seed Milk (ASM): it clocked in with 0.81% ash, 8.33% protein, 2.95% fat, a pH of 6, and 12.043% total solids. For comparison, hazelnut milk might have around 2.2-2.5% protein but higher fat (6.3-7.3%). The higher fat and lower protein in hazelnut milk could be because it often doesn’t go through a pressing process, so it keeps more of its natural fat. Looking at soy milk, you might see 0.43–0.87% ash, 1.273–3.240% protein, and 0.763–2.347% fat. Almond milk? Around 1.63–3.02% ash, 0.768–1.380% protein, and 3.833–8.257% fat. So, my ASM is looking pretty good, especially on the protein front! The lower numbers in some other plant milks often come down to higher dilution rates during production. The pH of ASM (6.0) is right in line with other plant-based milks, which is important for stability and how it tastes.

And what about the Apricot Seed Milk Powder (ASMP)? It had 2.68% moisture, 3.72% ash, an impressive 38.45% protein, 2.17% fat, a pH of 6, and a water activity of 0.154. Soymilk powder, for instance, might have around 48.79% protein and 28.77% fat. The protein in my ASMP was a bit lower, which could be due to the different starting material (apricot seeds vs. soybeans) and maybe some protein loss during the pressing of the apricot seeds. Also, spray drying settings can tweak the final composition. That low water activity (0.154) in ASMP is fantastic news – it means less chance of microbial growth and enzymatic activity, leading to better stability and a longer shelf life. Perfect for keeping in the pantry!

It’s clear that the type of raw material, how it’s processed, and the production parameters really shape the final chemical and physical properties of ASM and ASMP. Even when I reconstituted the ASMP for some tests (at 10% w/v), the overall nutritional trends and sensory vibes stayed consistent, confirming that the differences I saw were mainly due to processing, not just dilution.

Looking Good: Color and All That Jazz

Color is a biggie, right? It’s often the first thing we judge. For ASM, the L* value (that’s lightness) was 5.14. Cow’s milk, for comparison, is way up at around 81.89 – super opaque and glossy. My ASM was definitely darker and more opaque. Other plant milks vary: peanut milk around 56.62, almond milk about 64.38, and hazelnut milk can be as high as 83.4, similar to cow’s milk. Why the lower L* for ASM? It’s likely due to the unique makeup of apricot seeds and the processing. The higher protein in apricot seeds probably creates a denser, less translucent liquid. Also, I didn’t use commercial filtration methods like centrifugation or homogenization, which usually make plant milks lighter and clearer. To brighten up ASM, future experiments could explore things like high-pressure homogenization or ultrasonic treatment.

For the ASMP, the L* value was a lovely 91.96, with a* (-0.44) and b* (0.57) values indicating a bright, neutral-colored powder. Camel milk powder, for example, has a* and b* values of -1.49 and 9.00, showing more yellow due to its sugar composition. The lower a* and b* for ASMP might be because apricot seed products have less sugar. Sugar content can influence Maillard reactions during spray drying, which affects color. Plus, the protein-rich nature of ASMP likely contributes to less yellowing. So, while ASM might need a bit of a makeover in the looks department, ASMP is already a pretty sight, making it a great ingredient for various foods.

The Feel Factor: Physical Quirks of ASMP

Okay, let’s get physical with the ASMP! I looked at a bunch of properties:

• Wettability: How quickly it disperses in liquid. ASMP took 332 seconds. Almond milk powder is much quicker (13-22s), while spray-dried soy milk can range from 57-308s, and things like goat milk powder (418-594s) or coconut milk powder (722s) take longer. So, ASMP is in the ballpark but could be faster. This might be due to the surface properties of its proteins.
• Spreadability: 65.81%
• Solubility Index: 74.74%
• Bulk Density: 0.40 g/mL (compressed: 0.67 g/mL). This is a bit higher than almond milk powder (0.30-0.32 g/mL) and soy milk powder (0.21 g/mL), but comparable to avocado powder (0.37-0.49 g/mL) and coconut milk powder (0.38 g/mL). Higher protein and lower fat in ASMP might be the reason.
• Flowability (Carr Index, CI): 30.15%
• Cohesiveness (Hausner Ratio, HR): 1.28
• Hygroscopicity: How much moisture it absorbs from the air. ASMP was 16.96%. This is higher than almond milk powder (7.7-8.10%) and babassu coconut milk powder (6.98-9.86%). Higher hygroscopicity means it’s more sensitive to humidity and needs careful storage. Using carriers like maltodextrin during spray drying can help reduce this.
• Clumping: 27.33%

These physical traits are different from other plant-based milk powders mainly because of the unique starting material (apricot seed press cake), the spray-drying settings, and the amount of carrier used. The high hygroscopicity is a key takeaway – store ASMP carefully! Future work could tweak the formulation and drying to improve wettability and reduce that moisture-grabbing tendency.

Tiny but Mighty: Particle Size and What It Looks Like Up Close

Ever wondered what milk powder looks like super magnified? I did! First, I checked particle size. Interestingly, the solvent used for washing the powder before measuring made a big difference. Water-washed samples had tiny median particles (0.574 μm) and a wider size range. 2-propanol-washed samples had larger median particles (7.635 μm) but a narrower size distribution, which means better flow. The water-washed ones also had a much larger specific surface area, which is good for dissolving.

Compared to other powders, like avocado powder (11-34 μm median particle size), ASMP particles are quite different. This isn’t surprising, as raw materials, drying methods, and even the solvents used for analysis can all play a part. Particle size is super important: finer particles usually mean better solubility and a smoother feel, great for drinks. Larger particles can mean better flow and stability, good for things like baked goods.

Then, I peeked at ASMP using a scanning electron microscope (SEM). The images showed an irregular structure with particles of different sizes, and quite a bit of clumping. It looked like agglomerates formed from tiny particles, rather than separate, neat ones. This clumping often happens when there’s free fat or protein on the surface, or when water bridges form between particles. This cohesiveness affects how the powder flows and reconstitutes. The images (Fig. 1 in the original study, if you’re curious!) showed how spray drying changed the structure from the original APC. It seems the drying temperature plays a big role; my ASMP looked similar to powders dried at high temperatures, which can lead to more disintegration and affect bulk density. The maltodextrin I used as a carrier also likely influenced the particle shape and increased cohesiveness, as it makes the initial liquid more viscous. While maltodextrin can help by encapsulating bits and forming a stable film, the cohesiveness is something to keep an eye on for handling. Porosity is another factor – lower drying temps can make more porous particles that dissolve better. My higher temp might have made denser particles. Lots to think about for future tweaks!

The Building Blocks: Let’s Talk Amino Acids!

Amino acids are the building blocks of protein, and let me tell you, ASM and ASMP are packed with them! In ASM, Leucine (Leu) was the star, at 31.73 µg/mL. In ASMP, Leu was also top dog at a whopping 238.09 mg/g. Interestingly, Alanine (Ala) and Proline (Pro) weren’t detected in either. This kind of profile lines up with other plant protein sources, which is great news.

What’s really cool is the high content of essential amino acids – the ones our bodies can’t make. They made up 59% of total amino acids in ASM and nearly 61% in ASMP! Leucine, in particular, is famous for its role in muscle protein synthesis, making ASMP a potentially awesome supplement for athletes or anyone needing a high-quality protein boost. When I compared it to other plant milks, apricot kernel milk, with its high glutamic acid (Glu) and aspartic acid (Asp), looks like a strong contender, even meeting WHO recommendations for essential amino acids. Some plant milks, like almond, rice, and coconut, can fall short on protein and certain amino acids. Soy milk often does well, and oat milk is pretty good too, though sometimes low in methionine and lysine. My apricot kernel milk powder, with its high protein and amino acid lineup, really seems to stand out.

The differences in amino acid amounts between ASM and ASMP? Probably down to the processing. Drying the ASMP could concentrate some amino acids, while heat might degrade others. And, of course, the apricots themselves – where they’re grown, the soil, the climate – can all influence their amino acid makeup.

What’s That Smell? Volatiles and Aroma

Time to talk aroma! ASM had 11 volatile compounds, with benzaldehyde being the main one (79.15 µg/100 mL). This compound is key to that characteristic almond/apricot kernel smell. ASMP had 14 volatile compounds, and again, benzaldehyde was the most abundant, but at a much lower level (0.41 µg/kg). Why the drop? The spray-drying process, with its high heat, likely caused some of these volatile compounds to degrade or simply evaporate. It’s a common challenge when processing foods.

Benzaldehyde isn’t just about aroma; along with benzyl alcohol (another compound found), it’s used in some therapeutic applications, like for respiratory issues, and is even in cough syrups! The other volatiles I found, like hexanal (grassy, fresh), limonene (citrusy), nonanal (floral, fatty), and octanal (citrusy, fatty), all contribute to the overall flavor profile. Phenylethyl alcohol adds a rose-like, floral note. The presence of these compounds, especially benzaldehyde, gives ASM and ASMP that signature nutty, marzipan-like character.

The fact that benzaldehyde was so much higher in ASM than ASMP really shows how processing impacts aroma. To keep more of these lovely aroma compounds in the powder, future work could look at lower drying temperatures or using carriers that protect volatiles. It’s also interesting that some of these compounds, like benzaldehyde and benzyl alcohol, have reported antimicrobial, antioxidant, and anti-inflammatory properties. So, these apricot seed products could be more than just tasty – they could be functional foods with added health perks!

The Moment of Truth: Sensory Evaluation

So, how did my apricot creations fare with actual human tasters? I got a panel of ten semi-trained assessors to give their honest opinions. For the Apricot Seed Milk (ASM), which was pasteurized and cooled, the scores (on a 9-point scale where 9 is excellent) were:

• Appearance and Color: 3.6
• Taste: 4.0
• Odor: 4.3
• Structure/Texture: 4.3
• Overall Acceptability: 4.1

These scores suggest ASM was generally satisfactory, especially its texture and odor. The lower score for appearance (3.6) wasn’t a huge shock; plant milks often look a bit different from animal milk. We talked about its lower L* value (brightness) earlier. To jazz it up, maybe microfiltration or natural colorants like turmeric could help. The taste score of 4.0 is decent, but there’s room to grow. Plant milks can have unique, sometimes earthy, flavors. Adding things like cocoa, vanilla, or natural sweeteners could make ASM even more appealing.

Now for the Apricot Seed Milk Powder (ASMP). The panelists gave average scores over 4.0 for aggregation (how clumpy it was), color, apricot seed flavor intensity, and overall acceptability. That’s a pretty positive thumbs-up! They liked how the spray-drying preserved the physical and sensory bits. However, the “off-flavor” attribute scored just under 4.0. This means some panelists picked up on a slight unwanted taste, which could be from some lingering volatiles in the original press cake. This isn’t uncommon for plant-based protein powders; things like phenolic compounds can add bitterness, or free fatty acids can give soapy notes. These are natural components, but their effects can often be managed with smart processing and formulation.

Wrapping It All Up: My Apricot Adventure

So, what’s the bottom line? This whole journey showed that apricot seed press cake (APC) is a fantastic, protein-rich starting point for developing plant-based milk (ASM) and milk powder (ASMP). Remember, APC had nearly 50% protein! The ASM I made had a solid 8.33% protein, and the ASMP hit 38.45% protein with a nice low water activity, hinting at a good shelf life.

Sensory-wise, ASMP did pretty well (overall score > 4.0/9). ASM’s main hurdle seems to be its appearance, specifically that low brightness (L* = 5.14). And a big challenge is aroma: benzaldehyde, the star flavor compound, took a big hit during spray drying for ASMP. Plus, ASMP’s high hygroscopicity (it likes to absorb moisture) and longer wettability time mean there’s still some tweaking needed to perfect its physical stability and how easily it mixes.

Of course, every study has its limits. My sensory panel was small (just 10 people), and I only used one type of apricot (the Hacıhaliloğlu variety). Different apricots might give different results. Also, I didn’t dive into the health effects or how well the nutrients are absorbed by the body – that’s definitely for future research!

But even with these points, I’m really excited. Apricot seed-derived products show huge promise as sustainable, functional ingredients for the ever-expanding world of plant-based foods. There’s more work to be done, especially on keeping those lovely aromas intact, making them even tastier, and getting broader consumer feedback, but the potential is definitely there. From a humble apricot pit to a nutritious pour – how cool is that?

Source: Springer