Understanding Scoville Heat Unit (SHU) Testing: FoodSense vs. HPLC
- martinpeacock13
- Feb 16
- 4 min read
Updated: Feb 22
When it comes to measuring the heat level of chilies or chili powders, one common question we receive at FoodSense is about how our technology compares to High-Performance Liquid Chromatography (HPLC). Let's dive into this topic and explore why understanding these differences can be crucial for anyone involved in the spice industry.
The Challenge of Consistency
Imagine you're a chili powder breeder, handler, or dealer based in Southeast Asia. You've just received HPLC results indicating your product's Scoville Heat Unit (SHU) rating. But what if those numbers aren't as reliable as you thought?
To illustrate this issue, consider a scenario where the same chili sample was tested at three different labs:
Lab Results:
Lab A: 34,000 SHU
Lab B: 50,000 SHU
Lab C: 23,000 SHU
These discrepancies raise questions about consistency and reliability. The relative standard deviations (RSD) for these results were alarming, with values like 38%, 24%, and 7%. For a testing method to be considered reliable, the RSD should ideally be below 20%.
Why Labs May Differ
Often, labs aren't accustomed to being questioned about their results. When asked to explain these discrepancies:
Lab A was uncommunicative.
Lab B, a national lab with a focus on scientific rigor, engaged in discussions and provided more confidence.
Lab C remained non-transparent.
This highlights a significant issue: labs often operate without much oversight or accountability for their results.
FoodSense Generation 4: A Quick and Reliable Alternative
In contrast to the HPLC process—where samples are sent off and results can take days—the FoodSense Generation 4 device offers immediate, objective measurements. Here's how it performs:
Sample Testing Comparison: Four samples were tested using both FoodSense Gen 4 and a trusted lab (Lab B). The correlation between these methods was strong, with an R-squared value of 0.96.
Differences in Results:
Sample 1: 10% difference
Sample 2: 21% difference
Sample 3: 7% difference
Sample 4: 8% difference
These results show that FoodSense Generation 4 can provide consistent and reliable SHU ratings, especially when compared to a lab with proven credibility.
The Real Question: HPLC vs. HPLC
The real issue isn't how FoodSense compares to HPLC but rather how different HPLC labs compare against each other. Our findings suggest that variability in HPLC results can be significant, leading to inconsistencies and potential mistrust in the data.
Conclusion
For anyone involved in the chili industry, understanding these testing discrepancies is crucial. While HPLC remains a popular method, its variability can pose challenges. FoodSense Generation 4 offers a quick, reliable alternative with strong correlation to trusted lab results.
Q and A
The following are questions that have come in and answers FoodSense has provided.
1) Question - Are those samples 1 ~ 4 red pepper powder?
1) Answer - The samples 1 to 4 are red chilli powders.
2) Question - How do samples 1 ~ 4 differ (varieties, origins, red pepper powder size, etc.)?
2) Answer- The testing was was performed and paid for by a third party so details such as varieties, origins, red pepper powder size, etc. are unknown, part from being red chilli powders.
3) Question - Are the measurements from Labs 1, 2, and 3 a single measurement or an average of multiple measurements?
3) Answer - Each HPLC result is from a single measurement, the cost of HPLC means that only one test per sample is performed, which is the case here. So in summary each test was done once.
4) Question - How were the RSD values in the table calculated?
4) Answer - For Sample 1 the HPLC results were: Lab 1 = 34102 SHU, Lab 2 = 50591 SHU, Lab 3 = 23500 SHU, the RSD% for these three values = 38 %.
5) Question - In Labs 1, 2, and 3 data, the measurements from Labs 1 and 3 are similar, and the Lab 2 measurement is bigger than that of the other two.
5) Answer - The client who paid Lab 1, Lab 2 and Lab 3 to do the testing tried to interview Lab 1 and Lab 3, but the labs would not answer questions regarding testing. It was only Lab 2 who would talk to the client. The client determined that the only Lab that was reliable was Lab 2 whilst the other two labs would not provide evidence as to how they obtained the results. As a side note Lab 2 was a National Lab, whilst Lab 1 and 3 were private/for-profits.
6) Question - Why was the Lab 2 measurement selected as the comparison measurement with G4?
6) Answer - The comparison between FSG4 and Lab 2 was a decision made by the client, as Lab 1 and Lab 3 would not provide supporting evidence as to the validity of their results, whilst Lab 2 would so. The client effectively lost confidence in the results of Lab 1 and Lab 3.
7) Question - Are the sample preparation and measurement methods for Labs 1 to 3 the same or different? If different, what are the differences?
7) Answer - Labs 1 and Lab 3 would not communicate with the client and so how they obtained their HPLC results are unclear.
8) Question - Please explain any differences in sample preparation or measurement methods between Lab 2 and FSG4 if there was any.
8) Answer - Lab 2 was following AOAC 995.03, whilst the client applied a 1 in 100 dilution of teh chilli powder in chilli pot buffer for 24 hours and then tested the extractant.
9) Question - Are the FSG4 measurements a single measurement or an average of multi measurements?
9) Answer - The results give are single measurements.
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